“You’re looking for the writers, the musicians, the drama people, and the sociology majors.” That was the recruitment advice I got from the first person who ran a game for me at college. It’s not always accurate, but for people like us it’s a good start.
The big thing about finding a group is making sure you’re all playing the same game. Now, that doesn’t just mean all playing the same system, and all showing up at the same time. That part’s easy. The difficult part is figuring out the less obvious details.
One is what kind of game is being run: not all games are created equal. If you’re using an established system, how closely are you cleaving to the rules? Some people will be irritated by the constraints of a game that has no rules-flexibility, others will despise one in which things don’t always work the way the book says they do. Are you running something with a very definite plot, or are you giving your players a world and saying “Here it is; have fun”? Some people rail against plots that sweep them up, others prefer to let what’s supposed to happen guide their decisions. How much fighting is there going to be? Talking? Puzzle-solving? How useful are skills that don’t directly apply to the above?
Then you get to writing and characterization style, which matters a lot more than many people might think. I’ve seen a few cases of this going wrong. One was a game in which about 60% of the group were trying to be comparatively serious, and the other 40% had a tendency to goof off at every available opportunity and stretch the bounds of suspension of disbelief; there was a certain amount of grudge going between those sides, and when the fellow running the game got into it, things only got messier. There was one time in which a game had been introduced as a lighthearted run through a relatively safe neck of its world, adventurous but not taking itself too seriously, and—well, suffice it to say that most of the group was in a corresponding style, except for two members who looked like they’d stepped right out of a rather grim and very over-the-top barbarian fantasy novel. To say that this caused difficulties would be a minor understatement—sure, it was in only one game, but it was two entirely different stories.
And don’t forget the presence or absence of the fourth wall. If you’re the type who wants to run a game that could be publishable if the names were changed and the clear product identity markers were taken out, seeing the group refer to each other by name before actually being introduced, accept a character they barely know who has little in common with them (or, for that matter, try to hang onto a character who wouldn’t logically stay) with no apparent rationale beyond “He’s a PC”, constantly drop references or anachronisms in character, and in general beat on the fourth wall as much as they do their enemies can be highly frustrating. By the same token, someone who stays within the fourth wall in a game in which it is meant to be broken can be just as bad.
The short version is, you want to make sure that the group can agree on what the game is. The best way to do this is to tell your recruits all of your expectations. System, format, level of plot control, level of humor, how detailed you want their characters to be (trust me, this matters), how much of a tolerance or lack thereof you have for metagaming and cross-world references, what kind of story you expect to be telling (having subgenre examples or writing styles might work, or giving them a bit of an idea how you write), what sorts of situations are likeliest to crop up, and whatever else you think might be relevant.