So, I want to make an ocean based campaign, but I need some help with quests, monsters, npcs, etc. If you have any tips tricks suggestions, or explanations on how dc works, please let me know!

oh I'm also planning on including lots of mini bosses, as well as regular bosses, so lots of combat.

Do you want this to be IN the sea? Like underwater adventure? Or simply on the sea? Because if you want your adventure to be underwater then I would do a mermaid/man city (I don’t have a lot of experience with underwater adventures). But if you want your adventure ON the seas then you have more options, such as a pirate adventure. I’ll give you more details on either if you specify.

Make sure the players know what to expect.  Being on the sea, maybe someone will want to be a Grung or a Locothah (races that must be submerged in water every day to survive, often passed up for campaigns where that access to sufficient water would frequently not be available), and maybe others will want to specifically be a Sea Elf or a Triton, or a Fathomless Warlock (options with swim speeds), or they may want to be an Aarakocra or Owlin, or Fairy (races with fly speeds) or even a Hadozee (which even with the errata can still get to almost any part of a ship in one turn).

Definitely plan out the ship well, with enough space on it to be their base of operations, with places to store treasures and keep personal possessions, as well as most likely have NPC crew to operate the ship when the player-characters all leave to do interesting things.  This ship should be the characters' home for the campaign, which they'll want to protect and even upgrade.  Speaking of which, the expenses of paying the crew and keeping the ship in good repair and well stocked gives the party something to sink money into, so you can give them monetary rewards, and they have something to spend it on.

They can have adventures on various islands, for which you can take inspiration from classic stories like the Odyssey, the Iliad, and the tales of Sinbad.  On the ocean between islands they can encounter pirates, monsters, and weather events.  They might find a ghost-ship with notes in the Captain's quarters about a mysterious island with a great treasure they went to, but something terrible attacked them, and they weren't able to get the treasure, with an accompanying map to where to find the island.

Echoing the thoughts of @fayetteGamer think about the trade and the politics of the surrounding area. Why do the mini bosses and big bosses do what they do? Is it a situation where a big power has collapsed, setting off a scramble for land, trade rights, fishing territory. Are there alliances or is it a big free for all - are events orchestrated or random? Which races are present/involved? Who wants whom to go down? etc.

All of such thoughts give rise to plotlines, hooks, scenarios, progression of the story, the NPCs in it and the role the characters play in the story as they increase in wealth, status, ability and power

Go  treasure island style pirate  theme can't go wrong with that .

Quote from s9dyn2kpyf >>

Do you want this to be IN the sea? Like underwater adventure? Or simply on the sea? Because if you want your adventure to be underwater then I would do a mermaid/man city (I don’t have a lot of experience with underwater adventures). But if you want your adventure ON the seas then you have more options, such as a pirate adventure. I’ll give you more details on either if you specify.

 It's on the sea with possibly underwater segments, and I already know the antagonist will be a pirate

Quote from FayetteGamer >>

Make sure the players know what to expect.  Being on the sea, maybe someone will want to be a Grung or a Locothah (races that must be submerged in water every day to survive, often passed up for campaigns where that access to sufficient water would frequently not be available), and maybe others will want to specifically be a Sea Elf or a Triton, or a Fathomless Warlock (options with swim speeds), or they may want to be an Aarakocra or Owlin, or Fairy (races with fly speeds) or even a Hadozee (which even with the errata can still get to almost any part of a ship in one turn).

Definitely plan out the ship well, with enough space on it to be their base of operations, with places to store treasures and keep personal possessions, as well as most likely have NPC crew to operate the ship when the player-characters all leave to do interesting things.  This ship should be the characters' home for the campaign, which they'll want to protect and even upgrade.  Speaking of which, the expenses of paying the crew and keeping the ship in good repair and well stocked gives the party something to sink money into, so you can give them monetary rewards, and they have something to spend it on.

They can have adventures on various islands, for which you can take inspiration from classic stories like the Odyssey, the Iliad, and the tales of Sinbad.  On the ocean between islands they can encounter pirates, monsters, and weather events.  They might find a ghost-ship with notes in the Captain's quarters about a mysterious island with a great treasure they went to, but something terrible attacked them, and they weren't able to get the treasure, with an accompanying map to where to find the island.

 Thanks for the advice! Many of my players (and myself) are fairly new to dnd, so it'll just be races in the player's handbook, which might be a challenge because I don't think those have swim speeds

Quote from Jegblivervirkeligtraet >>

Echoing the thoughts of @fayetteGamer think about the trade and the politics of the surrounding area. Why do the mini bosses and big bosses do what they do? Is it a situation where a big power has collapsed, setting off a scramble for land, trade rights, fishing territory. Are there alliances or is it a big free for all - are events orchestrated or random? Which races are present/involved? Who wants whom to go down? etc.

All of such thoughts give rise to plotlines, hooks, scenarios, progression of the story, the NPCs in it and the role the characters play in the story as they increase in wealth, status, ability and power

 All good questions, I'll try to think about those

Quote from rammsorrow >>

Go  treasure island style pirate  theme can't go wrong with that .

i already am

Edit: Also, I don't mind if you suggest any good homebrews for this type of campaign, although I don't want to homebrew it too much

I would suggest that you watch the PotC for inspiration, not only is it good for D&D campaign inspiration in general, but you’re actually running a pirate adventure!

1) I would worry less about the stats of your players and more the stats of the ship, of course the player stats will be important when they go inland, but you definitely do not want to fudge on the details of the ship. Speaking of the ship, I would make it small (in the beginning), maybe small enough to where the players can man it almost by themselves, this will cut the costs of hirelings and give room for improvement, the players will (eventually) want a bigger ship (for treasure and combat ability), so I would have a stat block and map layout for at least 3 different ships besides the one they start with, You can make it clear that one ship is better then the others, or you can decide that different ships have different strengths (this one is faster and easier to manage, while this one is tougher and has more firepower). 

2)I would also make the crew more then just numbers on a financial statement, once again going back to PotC, you want some members of the crew (or all depending on the size) to have some value to the players, give them a basic stat block and some personality traits and flaws (you can go further by adding ideals and bonds). But just because they now have value to the players doesn’t mean you should be afraid to kill them off (or even have them betray the players), if they die to other pirates then the players will now have a reason to kill them, besides just “WE’RE PIRATES!! PREPARE TO DIE”. 

3) I would also (like previous people have said) make a series of different towns/ports. I would make at least 2 different ports of interest. Once AGAIN going back to PotC, I would make a Port royal (the place where you can get a lot of adventure hooks/powerful allies) and Tortuga (the place where they can find some basic crew members and sell stolen goods). You can always add some more ports as needed. You also want to have some cool islands, places where they can find treasure and combat. And perhaps after they do a decent amount of pirating they’ll catch the attention of a pirates guild, and should they join they’ll unlock a special location that can act as their home base outside of their ship. 

4) for enemies I would use primarily things like other pirates, skeletons/skeleton pirates (you would probably make them a bit stronger, especially their intellect and charisma), and of course you’re gonna want some mythological creatures such as Dragon turtles and the Kraken. You might want to throw in some merfolk for underwater adventures.

5) most importantly I would give them the freedom to choose what type of pirate they want to be. If the want to be humble merchants then you should let them, or if they want to be pirate warlords you should give them the options to buy more ships and start building a fleet. Regardless of how they want to play you should give them some universal enemies/allies.

This is all the advice I have for now, I hope it helps!

Ok, I wasn't planning on making the players pirates, but at least making them something similar might be interesting, so that might be fun. I should probably also give the players an NPC as a permanent crew member, suggesting them to do stuff like getting more hires.

Do you have any tips for creating quests, and how to go about them? And also, any tips for going about the first session?

For an ocean adventure you have to choose where the action is (it’s best not to have both otherwise the players can be a little overwhelmed)

1) The adventure is in the journey. For this type of play the characters will already know where they need to go for (insert reason here), But the issue is getting there. Whether it be monsters/pirates/natural disasters ETC there is going to be something that’s gonna try and stop the players. In the end the players fight the battle, then get their rewards at the location. This play styles quests won’t be as important as the enemies that block the way

2) The adventure is in the destination. This play style is less focused on HOW your players get their and more focused on WHAT they do when they get there, for this play style when the players are traveling you’ll probably just say something like “you travel to the location”, and then tell them what’s going on at the island. This play style has much more room for things like puzzles, social interactions, and other non combat encounters. 

for the first session I wouldn’t worry about adventuring, and focus on the players and their backstory’s, maybe even their ships backstory. This will also allow you to get the players opinions on what they want from this adventure, and then plan future sessions accordingly.

hope this helps!

ok, sounds good. Also, now I'm starting to think that it might not be an ocean campaign, but it probably will, because I'm already so interested on the idea. For now, just give me mostly general dm tips. Also, if the adventure was in the journey, would it be ok to have smaller destinations that there is also action at? And does "the adventure is the destination" also have room for combat encounters? I probably won't have as many of those in my campaign as I originally thought, but still.

Quote from Oceloto999 >>

ok, sounds good. Also, now I'm starting to think that it might not be an ocean campaign, but it probably will, because I'm already so interested on the idea. For now, just give me mostly general dm tips. Also, if the adventure was in the journey, would it be ok to have smaller destinations that there is also action at? And does "the adventure is the destination" also have room for combat encounters? I probably won't have as many of those in my campaign as I originally thought, but still.

 1) yes it does have room for small destination, maybe they get stuck on a shoal while traveling and have to get the ship unstuck, or they have to stop to get more supplies ETC.

2) yes it could be primarily combat, I only mentioned the other stuff since it can be difficult to squeeze that stuff into the story in most other adventure types

Here’s a few general tips

1) Always keep the players involved. If there ever comes a point in the story where the players feel like they’re railroading then they’ll get bored, so make sure they always (with maybe a few exceptions) have control over what they want to do

2) Keep the Characters involved. One mistake a lot of new DMs make us to ask the PLAYER how they’d act in (insert scenario here) and not how the CHARACTER would act. If the player likes to run headfirst into things, but the character likes to think them out, then you might want to tell the player to make his actions according to how the character would act. Of course if you have no care for character background/story then this rule goes out the window.

3) Keep your players in check. If one player starts acting out and ruining the game for others then you need to have a chat with that player, and sometimes even ask them to leave. The worst mistake any DM can make is to tolerate bad players, lots of DMs do this then loose control then get stuck in a game no one is having fun in.

this is all general advice, if you ask more specific questions the I can give more specific answers. I hope this helps!

okay, so i decided as i prepare my main campaign, i might do one off adventures in the meantime to get to know my players and their characters. also, do you have tips for getting players to share their character's backstory?