Party composition starts long before picking your character class.

Have you ever put together a game with all your friends thinking it’s going to be great only to realize after you start playing that it’s really not that great and you’re not getting along like you usually do even though you’ve been friends for years? This is because you didn’t vet the party. There are several beginning steps that need to be taken to make sure you’re game lasts more than 3 sessions.

First off, what kind of game are you running?

Silly, like a cartoon with cartoon violence and characters who might not make the optimum damage play every time.

This is where DNDTonight and most podcasts I’ve listened to fall.

Serious, more movie like with potentially more graphic violence and adult situations. Players are expected to be on the ball and do the best they can for the party because their decisions have serious consequences.

The players all need to be on board with the style of game that they are going to play. I’ve played in both, and they are both fun in different ways, but it’s not great when in a serious game someone tries to roll intimidation with a rubber chicken. Your actions need to fit the world that everyone is working to build.

It’s probably easier to build a silly game than a serious game but this alone isn’t enough to ensure a good player composition. Everyone has prior experiences with the game or with what they think the game is. It’s well worth your time when bringing together your players to ask each of them what they want the game to be and make sure that everyone is looking for the same thing. If someone wants to betray the party and someone else finds that to be the most annoying thing that can happen in a game you’re probably not going to have a great game on your hands. Eventually everyone’s going to have a bad time which is the opposite of what the game should be.

What world does everyone want to play in?

What theme are we talking? This can be dictated by the DM because that’s the kind of game you want to run, but even if it is. I still find it best to find out what themes people are interested in. Maybe you can tie some of their interests into the game you want to run so everyone has something to look forward to.
It might be worth putting together a list of 5 potential themes you want to run and make the potential players Rank Choice Vote so you can pick the most popular theme for your game.

Not everyone is going to make the cut

This one is the toughest part of DND or any RPG. Sometimes you’re going to have to tell people no. If everyone wants to play a silly undersea water adventure with sponges and squirrels, but one of your friends wants to play werewolves in old timey England it might be better to swap them out with someone who’s more into the underwater adventure.
I know this sucks, but trust me playing in a game you’re not into is not going to be good. Just let the person know that when you come around to putting together the next campaign you’ll pull together a great cast of furry critters who want to play that game as much as they do. Or perhaps suggest that someone else who couldn’t fit into your game might be able to start another game with them. It’s like playing Goldeneye there’s only 4 controllers but that doesn’t mean you can’t start another game.