Genesis of an Adventuring Party

So, you have a bunch of players and they all have the coolest concept ever for a character. What now?

First, sit everyone down before the first session and have a discussion and cover the following topics, not in any particular order:

Make everyone agree that whatever happens in the game, stays in the game. D&D is supposed to be fun for all involved and in character disputes or problems should never spill out and ruin real friendships. Whatever happens in game both you and the players should be having a good time and not getting angry with eachother. If you think your players can’t handle that, don’t play. There are more important things in life.

Have each player explain their character concept to the rest of the group. Seems like a waste of time but it’s not. First, it helps avoid later player conflict. If one player wants to be a dwarf whose family was slaughtered by drow and attacks them on sight and another wants to play a drow, you are going to have a problem. Having everyone discuss it off the bat lets you and the players come up with a way to work around it before the game gets rolling and there is bloodshed. Also, you would be surprised what sort of interesting shared backstory players will come up with in collaboration if you give them the chance.

Demand regular and updated copies of character sheets. Seem anal? Well it is, but for good reason. If you are going to craft interesting and challenging encounters then you will need to know each characters mechanical strengths and weaknesses. I’ve found the easiest way to do this is to tell your players to keep an online ‘master’ copy of their sheet. This way, if their sheet ever gets lost you can just print it out again or if they forget to bring their sheet you can just print them out a new copy on the spot. Personally, I prefer http://pifro.com/pro/ for this but there is no lack of sites that provide a free place to store your sheets online.

Make a party contract. Just a little agreement between characters about basic ways the party is going to split treasure and generally behave. You’d be shocked how many problems this can avoid.

Explain any houserules you plan to employ. If you are banning Divine Metamagic, tell your players before they build a character around it.

Also, talk to each player individually before the first session.

Find out if there are any bits of backstory or other details your players don’t want to share with the rest of the party yet. You need to know about it, even if it’s going to be a surprise for the rest of the group. You don’t want this to happen.

Ask about their preferred playstyle. If you don't already know it, find out what makes them tick as a player. What are the apects of the game they really look forward to? Some players like hack and slash others like heavy RP. Getting a sense of what each player likes will give you a pretty good idea of how to balance adventures such that everyone, including you, has a good time.

Find out where they want to go with the character, RP wise. What are the character's overall goals in life? Do they have a backstory or any background characters they think are important (not everyone will, if they don't, don't press them)? Is there any particular bit of plot regarding the character that they would really like to see happen? This information will help you craft many a plothook.

Find out where they want to go with the character, mechanically.
Are they already thinking about PRC's? If so, find out which ones so that you can work the existence of the fluff aspects into the game world, so you can willfully ignore the fluff aspects or so that you can tweak them as you desire. Feel free to ask if there is some stinky stinky cheese they'd really like to be able to pull of, just make sure that they know that you are just asking about it, not promising to give it to them.