Basically, I have been running oneshots at levels 3, 5, and 8 (local club rules for easy character building) and have been DMing a campaign at levels 8-13 (and still going), but have never gotten higher than level 13.
I want to start writing a shortish game for spelljammer which centres around levels 16-20, with some bigbad archlich as the main enemy who may or may not rhyme with "Pecna". The problem is, few people seem to run games at high level (as noted in other threads on here) and basically, players have so many shenanigans at this level that it's hard to predict their actions enough to write a plan from start to finish. I want to achieve minimal railroading, and basically want to say "To defeat the bigbad you will have to do activities 1-10, in some order, which are in these places", rather than "You feel like doing X" or "You talk to Boblin who tells you to do Y, which you do". Bascially, I want to write the world for them to explore in a semi-sandbox sort of way. I'm thinking along the lines of:
20 planetoids/significant locations in a star system, all with things to do
10 of them have important things for them to do there for the plot
The plot will advance at a set rate, so timekeeping will be important. They can either muck about and fall short at the end, or they can drive fast and be overprepared.
I want to structure it a little bit like a megadungeon, but with interchangable levels, so they might end up going somewhere too powerful for them. At high level, I consider this a low risk, because they can likely make slower progress, using more resources, and have access to resurrection spells and the like. Permadeath at this level is much less likely!
So, what hints, tips etc. do you have for planning higher level games? What are the biggest pitfalls for me to avoid when working with high level characters?
there's this REALLY great random wild space system generator(I cant find it again. :,( )
but I can give you some ideas (you have to come up with the names yourself)
a large, inhabitable planet with low gravity. unlike our earth, its a 50/50 ration of land to water. because of this, enormous, dinosaur-like life forms have evolved there. in the sole volcano on the planet's surface slumbers the Turrasque
a planet who'se ancient inhabitatnts built massive iron spikes that peirces the ley-lines of the planet. as a result, the entire planet is a wild magic zone, but the duration of any spells is doubled(yes, that includes instantaneous)
a planet taken over by giant evil crabs
a lone planet orbiting a dying star. the inhabitants have worshipped this star for as long as anyone can remember
a planet with no gravity, inabited by enormous, fish-like lifeforms
a living star who devouers planets to extend their own immemorial life-span
a ghost planet. it only exists in the ethereal plane, anyone else falls through
a planet entirely covered in water, home to an undersea metropolis
a divine dominion of the god tyr. the economy of this place is based on personal combat
a planet that was thought to be destroyed, only to appear 10,000 years later, on the other side of the Galaxy, with no signs of life
a zaratan the size of a planet
hpoe this helps
Rollback Post to RevisionRollBack
Pronouns: Any/All
About Me: Godless monster in human form bent on extending their natural life to unnatural extremes /general of the goose horde /Moderator of Vinstreb School for the Gifted /holder of the evil storyteller badge of no honor /king of madness /The FBI/ The Archmage of I CAST...!
Alignment: Lawful Evil
Fun Fact: i gain more power the more you post on my forum threads. MUAHAHAHAHAHAHAHAHAHA!!!!!!
Context: my campaign is 17th level right now, and has 8 PC's. I struggle a LOT with preparing something that challenges them these days.
My advice would be, if you plan to have a boss fight or BBEG, don't let the party be fully rested. Incorporate something, whether a puzzle or a separate fight or something else entirely, that can drain them of hopefully a lot of resources. The idea is to understand that, in all likelihood, you can't really stop the party at a certain point - but you CAN make it interesting for them.
One of my most recent memorable fights (they were 16th at the time) was an underwater battle with abberations. There was a beholder (among many other things) whose antimagic cone would 'switch off' the water breathing of party members. That alone added quite a fun dynamic to an otherwise pretty standard challenge for them.
Rollback Post to RevisionRollBack
I know what you're thinking: "In that flurry of blows, did he use all his ki points, or save one?" Well, are ya feeling lucky, punk?
there's this REALLY great random wild space system generator(I cant find it again. :,( )
but I can give you some ideas (you have to come up with the names yourself)
a large, inhabitable planet with low gravity. unlike our earth, its a 50/50 ration of land to water. because of this, enormous, dinosaur-like life forms have evolved there. in the sole volcano on the planet's surface slumbers the Turrasque
a planet who'se ancient inhabitatnts built massive iron spikes that peirces the ley-lines of the planet. as a result, the entire planet is a wild magic zone, but the duration of any spells is doubled(yes, that includes instantaneous)
a planet taken over by giant evil crabs
a lone planet orbiting a dying star. the inhabitants have worshipped this star for as long as anyone can remember
a planet with no gravity, inabited by enormous, fish-like lifeforms
a living star who devouers planets to extend their own immemorial life-span
a ghost planet. it only exists in the ethereal plane, anyone else falls through
a planet entirely covered in water, home to an undersea metropolis
a divine dominion of the god tyr. the economy of this place is based on personal combat
a planet that was thought to be destroyed, only to appear 10,000 years later, on the other side of the Galaxy, with no signs of life
a zaratan the size of a planet
hpoe this helps
All very cool ideas, thanks! I latched onto the Crabs one, made me htink of a world where time travels faster, meaning everything has evolved into the natural perfect organism.
Context: my campaign is 17th level right now, and has 8 PC's. I struggle a LOT with preparing something that challenges them these days.
My advice would be, if you plan to have a boss fight or BBEG, don't let the party be fully rested. Incorporate something, whether a puzzle or a separate fight or something else entirely, that can drain them of hopefully a lot of resources. The idea is to understand that, in all likelihood, you can't really stop the party at a certain point - but you CAN make it interesting for them.
One of my most recent memorable fights (they were 16th at the time) was an underwater battle with abberations. There was a beholder (among many other things) whose antimagic cone would 'switch off' the water breathing of party members. That alone added quite a fun dynamic to an otherwise pretty standard challenge for them.
Good call on using the environment to make it tough. I challenged my campaign at level 9 with 5 of them with a single roper, which was underwater, lurking in the murk. The one person it grabbed did escape, but it led to a lot of panic!
My current thought is to make a spelljammer game within a single star system, which I plan to map out carefully with the map as a prop (allowing a treasure-hunt of clues and riddles). I aim to frame the game as a treasure hunt for an ancient power, and then transition into a fight against an evil demigod. Hopefully, the reveal will be neat enough that they don't twig too soon! The map I plan on making a coordinate system to mark travel, which will hopefully make it easy to track navigation.
Currently roughly mapping the system, so suggestions for planets and cool things to add are welcome! So far I have a few planetoids and a couple of asteroid belts, as well as a large planet which is dangerous in its own ways, but is a verdant paradise. It's so good, you'll never want to leave. ever.
If you liked the crabs idea, I have a reference/interesting idea. The crabs are crab-cats!! (Yes, any viewer or fan of the Why Files reading, to answer your obvious question this is a reference to Hecklefish's "Fear the crab-cat!!")
Rollback Post to RevisionRollBack
In the words of the great philosopher, Unicorse, "Aaaannnnd why should I care??"
Best quote from a book ever: "If you love with your eyes, death is forever. If you love with your heart, there is no such thing as parting."- Jonah Cook, Ascendant, Songs of Chaos by Michael R. Miller. Highly recommend
Enforce the adventuring day, and limit short rests to twice per in game day. Seriously, the difference this can make to 'fixing' high level play is amazing. However, you also need to consider what magic items and suchlike that players have access to.
Other things I find necessary at those levels are:
Envrionmental effects (difficult terrain, areas of anti-magic, areas of wild magic, poison spores from plants, extreme cold or heat forcing constitution checks)
Multi-part encounters (reinforcements arriving after an alarm has been sounded)
Interesting environments (rickety scaffolding that's easy to damage, a trap that can be set off by the enemies, ballistae or other similar static weaponry, plentiful cover, elevation)
Using high level enemy abilities immediately (don't wait around to get that 9th level spell off, get it off straight away).
Double-tap downed player characters (seriously, too many parties get used to letting the unconscious player characters make death saving throws. When enemies start targeting the unconscious party members it both forces uses of high level healing and resurrection spells/scrolls. If the party have access to Raise Dead, Ressurection, Revivfy or similar make them use it.)
Focus fire on the flimisier player characters (when a dozen wights all start attacking the glass cannon wizard...).
Ultimately, the problem with high level play is how best to retain balance. The answer in my experience is to find ways of wicking away the resources that player characters have. Those spell slots, potions, scrolls and hit die need to be spent.
So the biggest single piece of advice I have: enforce the adventuring day. Six to eight medium to hard encounters per adventuring day. Average just two short rests per adventuring day. These are core rules in 5e and should be adhered to. You'll find this stuff in the DMG.
If you're running any 2024 rules, I'd advise waiting for the 2024 DMG before you attempt higher levels. If Crawford and his team are competent, they'll tell us there what the adventuring day for 5.5e should look like there.
A thing to remember about high level play is... PCs have access to a ton of healing. A perfectly reasonable threat level is that by the end of the villain's first action half the party is at zero hit points, or a smaller number are outright dead (no monster in the game does that much damage).
A thing to remember about high level play is... PCs have access to a ton of healing. A perfectly reasonable threat level is that by the end of the villain's first action half the party is at zero hit points, or a smaller number are outright dead (no monster in the game does that much damage).
A thing to remember about high level play is... PCs have access to a ton of healing. A perfectly reasonable threat level is that by the end of the villain's first action half the party is at zero hit points, or a smaller number are outright dead (no monster in the game does that much damage).
It deals 12d12 psychic if the character has more than 100hp
Which is nowhere near enough against a tier 4 party; that's a measly 78 damage, it won't even drop one PC. Meteor Swarm (140 damage) with a high save DC is probably the closest, but because it does elemental damage and involves a dex save (thus subject to evasion) it's still on the low side, and I'm not aware of any monster stat blocks that actually have that spell listed.
Also consider uprating badguys. Up against an arch Wizard Lich? Don’t be scared to give extra spell slots - even an extra L9 slot - blow your party’s mind when your L20 Lich arch Wizard turns out to be a L25 supreme sorcerer casting their second maximized meateor swarm.
At that level 2 common - 2 uncommon - 2 rare - 1 very rare is a fair starting point gear wise. + a few thousand GP for consumables a bag of holding and the like.
My usual format for that level game is story / skirmish / story / main fight of the session / mop up set the stage for next session. No rests except between sessions and not always then either.
I would have a session zero and dry run a skirmish to get a sense of the players knowledge and ability with their classes ----- a group of savvy adventurers is a very different thing than a group that is playing a level 16 for the first time. You need to have a sense of their overall skill set or the balance will be off from the start.
A thing to remember about high level play is... PCs have access to a ton of healing. A perfectly reasonable threat level is that by the end of the villain's first action half the party is at zero hit points, or a smaller number are outright dead (no monster in the game does that much damage).
There are two main problems with this approach.
1) If the BBEG can knock out 1/2 the party in one round. They can take out the other half in round 2. Random numbers are a thing and you can't rely on the entire party even rolling higher than a 5.
2) Characters who are unconscious or dead after the first round have nothing to do, possibly for the entire fight. This kind of approach creates a situation that can be less fun for a significant number of players.
You can end up with combats that last longer this way but is mostly because the PCs power is reduced and action economy shifts towards the NPCs.
I think Martin's post covered some of the tactics useful to making higher level play fun for everyone.
Just to expand on some of them
1) Add environmental and tactical problems to overcome in addition to the NPCs. Perhaps introduce a timer in the form of a set of runes that need to be removed from a setting, or a bunch of torches that have to be removed from sconces and subsequently dowsed - actions that the PCs are forced to engage in during the combat or else worse things happen. This will drain the PC action economy a bit and give them something to think about in terms of dealing with opponents vs environmental hazards.
2) Never have a boss by themselves. Ideally have 2-4 pretty much equivalent nasty threats or have the boss with a few almost as powerful minions. This is again to try to balance the action economy a bit as well as avoiding a situation where the party gets to focus all resources on one creature and finish the event quickly (unless that is the goal).
3) Depending on the party, they are usually very able to deal with threats that are far above the party level. However, be ready with a plan B if luck doesn't work out and everyone fails a critical save or things go sideways. Using waves of attackers, reinforcements, or allied NPCs or additional combatant factions in the combat can allow the DM to both gauge how the battle is going and control whether those additional forces show up AND allow the PCs to face more powerful and threatening opponents who may spend part of their time focused on the other factions in the fight while posing a huge threat to the occasional PC when they turn their attention to them.
The key is to have variety, powerful opponents - especially some spellcasters - and fights that don't necessarily reveal all the opponents/allies/other participants at the beginning so that the DM can adjust as they see fit - though honestly, players usually love the occasional fight that makes their characters feel especially powerful by curb stomping their foes, as much as they might like the ones that can be a nail biter.
A thing to remember about high level play is... PCs have access to a ton of healing. A perfectly reasonable threat level is that by the end of the villain's first action half the party is at zero hit points, or a smaller number are outright dead (no monster in the game does that much damage).
There are two main problems with this approach.
1) If the BBEG can knock out 1/2 the party in one round. They can take out the other half in round 2. Random numbers are a thing and you can't rely on the entire party even rolling higher than a 5.
2) Characters who are unconscious or dead after the first round have nothing to do, possibly for the entire fight. This kind of approach creates a situation that can be less fun for a significant number of players.
I have routinely rendered characters unconscious in the first round of the fight. All it does is force someone to expend healing resources to get them back up, depending on initiative order they might lose one action but quite unlikely to be more by mid to late tier 2. In tier 4, mass heal is generally a total reset of all damage taken, and even in lower tiers there's just a lot of healing that's pretty trivially available.
Its not my style to start an encounter with 1/2 a TPK. Maybe one player on occasion if they triggered a trap or have Symbol tripped when the 3rd player walks over the glyph and hit the group for 10d10 but just having the intention to put 1/2 the group down out of the gate seems heavy handed.
Its not a contest - the DM can always win if you just toss enough DPS at a group they will die.
Making the encounter have interesting mechanics is much more my preferred method.
Martintheactor and David42 really cover the bases here.
Let the players use their powerful abilities. The point is to have situations or environments where they *need* those high-level abilities just to have a chance. Urgency and limited opportunities to rest--whether "adventuring day" or other pressure--give players a chance to dig deep into their vast reservoir of abilities. That's why they have them! Harsh environments illustrate why those "situational" spells and non-combat abilities are actually useful. Give your party that experience of winning not by Meteor Swarm but by Ray of Frost or Action Surge, at the 11th hour, when all other resources are spent.
How do I prepare a high level game... Work, Hours upon hours of work. developing Maps, NPC's , Tweaking Monsters, Building encounters and most importantly developing the story My players want more than just dice rolling and special abilities.
How do I prepare a high level game... Work, Hours upon hours of work. developing Maps, NPC's , Tweaking Monsters, Building encounters and most importantly developing the story My players want more than just dice rolling and special abilities.
True that! Although a few friends where bored yesterday and I through together a 1 shot for a group of L14 players in about an hour - custom map - custom NPC's - quick plot line and lots of combat. I always spend a lot of time on it if its one of my regular groups but a quick pick up game with minimal prep can be good as well if your comfortable with AI and one of the VTT's
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Basically, I have been running oneshots at levels 3, 5, and 8 (local club rules for easy character building) and have been DMing a campaign at levels 8-13 (and still going), but have never gotten higher than level 13.
I want to start writing a shortish game for spelljammer which centres around levels 16-20, with some bigbad archlich as the main enemy who may or may not rhyme with "Pecna". The problem is, few people seem to run games at high level (as noted in other threads on here) and basically, players have so many shenanigans at this level that it's hard to predict their actions enough to write a plan from start to finish. I want to achieve minimal railroading, and basically want to say "To defeat the bigbad you will have to do activities 1-10, in some order, which are in these places", rather than "You feel like doing X" or "You talk to Boblin who tells you to do Y, which you do". Bascially, I want to write the world for them to explore in a semi-sandbox sort of way. I'm thinking along the lines of:
20 planetoids/significant locations in a star system, all with things to do
10 of them have important things for them to do there for the plot
The plot will advance at a set rate, so timekeeping will be important. They can either muck about and fall short at the end, or they can drive fast and be overprepared.
I want to structure it a little bit like a megadungeon, but with interchangable levels, so they might end up going somewhere too powerful for them. At high level, I consider this a low risk, because they can likely make slower progress, using more resources, and have access to resurrection spells and the like. Permadeath at this level is much less likely!
So, what hints, tips etc. do you have for planning higher level games? What are the biggest pitfalls for me to avoid when working with high level characters?
Make your Artificer work with any other class with 174 Multiclassing Feats for your Artificer Multiclass Character!
DM's Guild Releases on This Thread Or check them all out on DMs Guild!
DrivethruRPG Releases on This Thread - latest release: My Character is a Werewolf: balanced rules for Lycanthropy!
I have started discussing/reviewing 3rd party D&D content on Substack - stay tuned for semi-regular posts!
i just planned out a spelljammer campaign myself.
there's this REALLY great random wild space system generator(I cant find it again. :,( )
but I can give you some ideas (you have to come up with the names yourself)
a large, inhabitable planet with low gravity. unlike our earth, its a 50/50 ration of land to water. because of this, enormous, dinosaur-like life forms have evolved there. in the sole volcano on the planet's surface slumbers the Turrasque
a planet who'se ancient inhabitatnts built massive iron spikes that peirces the ley-lines of the planet. as a result, the entire planet is a wild magic zone, but the duration of any spells is doubled(yes, that includes instantaneous)
a planet taken over by giant evil crabs
a lone planet orbiting a dying star. the inhabitants have worshipped this star for as long as anyone can remember
a planet with no gravity, inabited by enormous, fish-like lifeforms
a living star who devouers planets to extend their own immemorial life-span
a ghost planet. it only exists in the ethereal plane, anyone else falls through
a planet entirely covered in water, home to an undersea metropolis
a divine dominion of the god tyr. the economy of this place is based on personal combat
a planet that was thought to be destroyed, only to appear 10,000 years later, on the other side of the Galaxy, with no signs of life
a zaratan the size of a planet
hpoe this helps
Pronouns: Any/All
About Me: Godless monster in human form bent on extending their natural life to unnatural extremes /general of the goose horde /Moderator of Vinstreb School for the Gifted /holder of the evil storyteller badge of no honor /king of madness /The FBI/ The Archmage of I CAST...!
Alignment: Lawful Evil
Fun Fact: i gain more power the more you post on my forum threads. MUAHAHAHAHAHAHAHAHAHA!!!!!!
Context: my campaign is 17th level right now, and has 8 PC's. I struggle a LOT with preparing something that challenges them these days.
My advice would be, if you plan to have a boss fight or BBEG, don't let the party be fully rested. Incorporate something, whether a puzzle or a separate fight or something else entirely, that can drain them of hopefully a lot of resources. The idea is to understand that, in all likelihood, you can't really stop the party at a certain point - but you CAN make it interesting for them.
One of my most recent memorable fights (they were 16th at the time) was an underwater battle with abberations. There was a beholder (among many other things) whose antimagic cone would 'switch off' the water breathing of party members. That alone added quite a fun dynamic to an otherwise pretty standard challenge for them.
I know what you're thinking: "In that flurry of blows, did he use all his ki points, or save one?" Well, are ya feeling lucky, punk?
All very cool ideas, thanks! I latched onto the Crabs one, made me htink of a world where time travels faster, meaning everything has evolved into the natural perfect organism.
Good call on using the environment to make it tough. I challenged my campaign at level 9 with 5 of them with a single roper, which was underwater, lurking in the murk. The one person it grabbed did escape, but it led to a lot of panic!
My current thought is to make a spelljammer game within a single star system, which I plan to map out carefully with the map as a prop (allowing a treasure-hunt of clues and riddles). I aim to frame the game as a treasure hunt for an ancient power, and then transition into a fight against an evil demigod. Hopefully, the reveal will be neat enough that they don't twig too soon! The map I plan on making a coordinate system to mark travel, which will hopefully make it easy to track navigation.
Currently roughly mapping the system, so suggestions for planets and cool things to add are welcome! So far I have a few planetoids and a couple of asteroid belts, as well as a large planet which is dangerous in its own ways, but is a verdant paradise. It's so good, you'll never want to leave. ever.
Make your Artificer work with any other class with 174 Multiclassing Feats for your Artificer Multiclass Character!
DM's Guild Releases on This Thread Or check them all out on DMs Guild!
DrivethruRPG Releases on This Thread - latest release: My Character is a Werewolf: balanced rules for Lycanthropy!
I have started discussing/reviewing 3rd party D&D content on Substack - stay tuned for semi-regular posts!
If you liked the crabs idea, I have a reference/interesting idea. The crabs are crab-cats!! (Yes, any viewer or fan of the Why Files reading, to answer your obvious question this is a reference to Hecklefish's "Fear the crab-cat!!")
In the words of the great philosopher, Unicorse, "Aaaannnnd why should I care??"
Best quote from a book ever: "If you love with your eyes, death is forever. If you love with your heart, there is no such thing as parting."- Jonah Cook, Ascendant, Songs of Chaos by Michael R. Miller. Highly recommend
Enforce the adventuring day, and limit short rests to twice per in game day. Seriously, the difference this can make to 'fixing' high level play is amazing. However, you also need to consider what magic items and suchlike that players have access to.
Other things I find necessary at those levels are:
Ultimately, the problem with high level play is how best to retain balance. The answer in my experience is to find ways of wicking away the resources that player characters have. Those spell slots, potions, scrolls and hit die need to be spent.
So the biggest single piece of advice I have: enforce the adventuring day. Six to eight medium to hard encounters per adventuring day. Average just two short rests per adventuring day. These are core rules in 5e and should be adhered to. You'll find this stuff in the DMG.
If you're running any 2024 rules, I'd advise waiting for the 2024 DMG before you attempt higher levels. If Crawford and his team are competent, they'll tell us there what the adventuring day for 5.5e should look like there.
DM session planning template - My version of maps for 'Lost Mine of Phandelver' - Send your party to The Circus - Other DM Resources - Maps, Tokens, Quests - 'Better' Player Character Injury Tables?
Actor, Writer, Director & Teacher by day - GM/DM in my off hours.
A thing to remember about high level play is... PCs have access to a ton of healing. A perfectly reasonable threat level is that by the end of the villain's first action half the party is at zero hit points, or a smaller number are outright dead (no monster in the game does that much damage).
The new Power Word Kill Power Word Kill - Spells - D&D Beyond (dndbeyond.com) from the 2024 rules would like to have a word with you.
It deals 12d12 psychic if the character has more than 100hp
DM session planning template - My version of maps for 'Lost Mine of Phandelver' - Send your party to The Circus - Other DM Resources - Maps, Tokens, Quests - 'Better' Player Character Injury Tables?
Actor, Writer, Director & Teacher by day - GM/DM in my off hours.
Which is nowhere near enough against a tier 4 party; that's a measly 78 damage, it won't even drop one PC. Meteor Swarm (140 damage) with a high save DC is probably the closest, but because it does elemental damage and involves a dex save (thus subject to evasion) it's still on the low side, and I'm not aware of any monster stat blocks that actually have that spell listed.
Also consider uprating badguys. Up against an arch Wizard Lich? Don’t be scared to give extra spell slots - even an extra L9 slot - blow your party’s mind when your L20 Lich arch Wizard turns out to be a L25 supreme sorcerer casting their second maximized meateor swarm.
Wisea$$ DM and Player since 1979.
For levels 16-20 I would recommend the following:
Allow players to roll stats on D&D Beyond.
At that level 2 common - 2 uncommon - 2 rare - 1 very rare is a fair starting point gear wise. + a few thousand GP for consumables a bag of holding and the like.
My usual format for that level game is story / skirmish / story / main fight of the session / mop up set the stage for next session. No rests except between sessions and not always then either.
I would have a session zero and dry run a skirmish to get a sense of the players knowledge and ability with their classes ----- a group of savvy adventurers is a very different thing than a group that is playing a level 16 for the first time. You need to have a sense of their overall skill set or the balance will be off from the start.
There are two main problems with this approach.
1) If the BBEG can knock out 1/2 the party in one round. They can take out the other half in round 2. Random numbers are a thing and you can't rely on the entire party even rolling higher than a 5.
2) Characters who are unconscious or dead after the first round have nothing to do, possibly for the entire fight. This kind of approach creates a situation that can be less fun for a significant number of players.
You can end up with combats that last longer this way but is mostly because the PCs power is reduced and action economy shifts towards the NPCs.
I think Martin's post covered some of the tactics useful to making higher level play fun for everyone.
Just to expand on some of them
1) Add environmental and tactical problems to overcome in addition to the NPCs. Perhaps introduce a timer in the form of a set of runes that need to be removed from a setting, or a bunch of torches that have to be removed from sconces and subsequently dowsed - actions that the PCs are forced to engage in during the combat or else worse things happen. This will drain the PC action economy a bit and give them something to think about in terms of dealing with opponents vs environmental hazards.
2) Never have a boss by themselves. Ideally have 2-4 pretty much equivalent nasty threats or have the boss with a few almost as powerful minions. This is again to try to balance the action economy a bit as well as avoiding a situation where the party gets to focus all resources on one creature and finish the event quickly (unless that is the goal).
3) Depending on the party, they are usually very able to deal with threats that are far above the party level. However, be ready with a plan B if luck doesn't work out and everyone fails a critical save or things go sideways. Using waves of attackers, reinforcements, or allied NPCs or additional combatant factions in the combat can allow the DM to both gauge how the battle is going and control whether those additional forces show up AND allow the PCs to face more powerful and threatening opponents who may spend part of their time focused on the other factions in the fight while posing a huge threat to the occasional PC when they turn their attention to them.
The key is to have variety, powerful opponents - especially some spellcasters - and fights that don't necessarily reveal all the opponents/allies/other participants at the beginning so that the DM can adjust as they see fit - though honestly, players usually love the occasional fight that makes their characters feel especially powerful by curb stomping their foes, as much as they might like the ones that can be a nail biter.
I have routinely rendered characters unconscious in the first round of the fight. All it does is force someone to expend healing resources to get them back up, depending on initiative order they might lose one action but quite unlikely to be more by mid to late tier 2. In tier 4, mass heal is generally a total reset of all damage taken, and even in lower tiers there's just a lot of healing that's pretty trivially available.
To each their own -
Its not my style to start an encounter with 1/2 a TPK. Maybe one player on occasion if they triggered a trap or have Symbol tripped when the 3rd player walks over the glyph and hit the group for 10d10 but just having the intention to put 1/2 the group down out of the gate seems heavy handed.
Its not a contest - the DM can always win if you just toss enough DPS at a group they will die.
Making the encounter have interesting mechanics is much more my preferred method.
Martintheactor and David42 really cover the bases here.
Let the players use their powerful abilities. The point is to have situations or environments where they *need* those high-level abilities just to have a chance. Urgency and limited opportunities to rest--whether "adventuring day" or other pressure--give players a chance to dig deep into their vast reservoir of abilities. That's why they have them! Harsh environments illustrate why those "situational" spells and non-combat abilities are actually useful. Give your party that experience of winning not by Meteor Swarm but by Ray of Frost or Action Surge, at the 11th hour, when all other resources are spent.
How do I prepare a high level game... Work, Hours upon hours of work. developing Maps, NPC's , Tweaking Monsters, Building encounters and most importantly developing the story My players want more than just dice rolling and special abilities.
True that! Although a few friends where bored yesterday and I through together a 1 shot for a group of L14 players in about an hour - custom map - custom NPC's - quick plot line and lots of combat. I always spend a lot of time on it if its one of my regular groups but a quick pick up game with minimal prep can be good as well if your comfortable with AI and one of the VTT's