Hi all, 

I'm planning and creating my own game and i was hoping anyone would help to suggest on how to prepare for any unexpected plays from the players?

Ah, the eternal question of the DM.

Fundamentally, the only real answer is "get used to it".

That's not all that helpful, though. There's several types of unexpected player actions:

- The one that usually discombobulates newer GMs is when they don't engage with the adventure. You set up the scenario, and they're just like "Nah". (Or worse, don''t even notice the giant neon signs saying "Yo! Adventure! Right here!")

There are several ways around it. I'm fond of waving many, many plot hooks at them until they bite on some, then developing those more, while still dropping new hooks as we go.

A much easier approach for newer DMs is to just get the players, out of character, to agree to stay in the box presented to them: "I made this dungeon. We're going to be exploring it.", or to accept a mission-based campaign setup: "You all work for the local lord/church/wizard/mysterious cloaked stranger who's totally not the Big Bad messing with you". As you go along, you can loosen up the structure.

- Then there's the in-the-moment surprises, when they do something completely out of left field, like mouth off to the king, or stab the barkeep, or whatever. You just have to roll with these. The occasional "Are you sure?" often helps stave off the worst of these, but players are going to be chaos muppets.

- The easiest type to handle is when they tell you they're going to do something you just weren't at all expecting. At the very start of my current game, where the setup was "It's a spelljammer game. You all hire on to crew a perfectly normal sailing ship", and then they get out into space, and the guy who hired them gets dead in a way that leaves them with the ship, an artifact, and one of many plot hooks, with no NPC to tell them what to do, and their first reaction was "We're going to raise the NPC!"

With these, at least, you get to think before having to deal. I suggest running with it instead of shooting them down. When the players make missions for themselves, you don't need to hook them in. Sometimes, it's going to mean you're running a different game than you thought.

This will happen to you a lot. Players are unpredictable, fickle, creative, impulsive and distractible little paranoids, bless their hearts. As you spend more time DMing in general, and DMing your particular group of noodleheads, you'll develop a better sense for what things they might do. But they'll surprise you even after you get to know them well. 

Tip 1: Don't bother trying to anticipate every outcome. You can't, and you'll burn out attempting it.  

Tip 2: Know your world. If you're aware of the broad strokes of your setting, the villains' activities/goals, and some NPC motivations, and you can better adapt to how the party swerves. Remember that the game world is progressing even if the players aren't investigating it. So for example, orcs are gonna raid Townsville whether or not the party takes up the quest...

Tip 3: Give yourself time. You'll grow more comfortable with improv on a story level as you gain experience, and you'll also be able to make more confident rulings too. It's okay to end session early if they really throw you for a loop you aren't prepped to handle, and it's also okay to just make a decision on the fly and figure it out as you go along. 

Improvise. Adapt. Overcome. 

In addition to the random tables in the DM's Guide, there's plenty of random generators online you can use to create something on the spur of the moment. If you're the type that likes to prepare more than the bare minimum, during your prep work just create additional content that you put on a random table. When the players veer off unexpectedly then have a roll on that table and use it. (I like to have the players roll so their fate is in their hands.) You can pre-generate generic NPCs and just pull them out as you need them, filling in their specific role as you go. 

When you have nothing else, throw in a random combat encounter to run the session's clock down. Then you'll have until your next session to prepare. 

In addition to what Rathkryn just said, I might suggest creating at least one, preferably more, encounters that have something to do with the story you want to run. Not too closely, as then it will feel railroaded (they'll feel that their actions don't matter), but it will let you defualt to an enjoyable encounter that has something to do with the story. If the encounter is good enough, and they don't trigger it, you can always find a way to stick in into your game at a later date. 

If you are using random encounter tables, I favor rolling them before the game, so that you have a bit of time to think about the encounter and how best to use it.

In all cases, having multiple backups is useful, as it gives you multiple choices to choose from, and you can decide which one fits best.

Quote from jl8e >>

Ah, the eternal question of the DM.

Fundamentally, the only real answer is "get used to it".

That's not all that helpful, though. There's several types of unexpected player actions:

- The one that usually discombobulates newer GMs is when they don't engage with the adventure. You set up the scenario, and they're just like "Nah". (Or worse, don''t even notice the giant neon signs saying "Yo! Adventure! Right here!")

There are several ways around it. I'm fond of waving many, many plot hooks at them until they bite on some, then developing those more, while still dropping new hooks as we go.

A much easier approach for newer DMs is to just get the players, out of character, to agree to stay in the box presented to them: "I made this dungeon. We're going to be exploring it.", or to accept a mission-based campaign setup: "You all work for the local lord/church/wizard/mysterious cloaked stranger who's totally not the Big Bad messing with you". As you go along, you can loosen up the structure.

- Then there's the in-the-moment surprises, when they do something completely out of left field, like mouth off to the king, or stab the barkeep, or whatever. You just have to roll with these. The occasional "Are you sure?" often helps stave off the worst of these, but players are going to be chaos muppets.

- The easiest type to handle is when they tell you they're going to do something you just weren't at all expecting. At the very start of my current game, where the setup was "It's a spelljammer game. You all hire on to crew a perfectly normal sailing ship", and then they get out into space, and the guy who hired them gets dead in a way that leaves them with the ship, an artifact, and one of many plot hooks, with no NPC to tell them what to do, and their first reaction was "We're going to raise the NPC!"

With these, at least, you get to think before having to deal. I suggest running with it instead of shooting them down. When the players make missions for themselves, you don't need to hook them in. Sometimes, it's going to mean you're running a different game than you thought.

 Yes. Just yes. This is what you need.

'Scuse me, but this is the D&D player all over. In all my years of DMing, Every player acts weird. 'cos i want to, here are a few examples from my campaigns:

1.  In my first ever game, the team rogue tried to pick every lock he saw. Every last one. He accidentally locked three doors in that one session.
2. In a recent game, the team wizard decided to cast animate object on the next thing he saw, which happened to be the fighter's greatsword. It actually helped the party in a way, having a talking, flying greatsword peeking around corners and assassinating people.
3. In a mission I was playing, My fighter fed some magic cheese to a random mouse in a sewer, turning it into a giant mouse that attacked the party. Yep, I've been there.

I think you might get the point. Your players will do stuff you cannot anticipate. Do not create a linear mission. That's all i can say.

Oh yeah, I'm recent on beyond but I've played for for, like, 10 years and DMed for 4.