I thought I'd take a short off the path delve into roleplaying. Not much to do with my story, but I thought I would share some ideas.
1) Everyone pitches in for dinner, (or lunch, or what ever). Maybe this is in the form of a side dish or snacks or drinks. We found that you, as a group, don't feel so upset at someone for eating all the food if they did contribute. Roleplaying with a group of young men made me realize they eat a lot, so making sure it wasn't just one person bringing the food was a good idea.
2) No politics. Or what ever you know is going to set someone off. Our college group of roleplayers had some very different politics and though, unlike today, we could have a civilized conversation and agree to disagree on stuff the roleplaying table is not the place to bring this stuff up. Stick to the game. Yes, you can tangent to horrible professors, homework due, work assignment deadlines, or even the commute if you have one, but stay off the sticky topics if you want to have a fun night.
3) Make sure as the GM you have everything ready to go and extra stuff for your players. Our newer group of roleplayers didn't have dice and the like, but we knew that going in, so we made sure they had some dice to role and we had crisp new character sheets printed so they could make up their first ever characters. It makes it so much smoother to have everything prepped, sorta like real life :)
4) Establish rules on rolling, take backs, and what a character knows. This is much better to figure out before you sit down. They don't have to be perfectly specific, but some guide lines are good. Like everyone, except the GM, rolls out in the open and don't help a player if your character isn't in the room. (This is tempting as a player all the time.)
Happy Gaming!