So far most of the thread has been about the tec. end of the gig and performance, but remember it doesn't end there. You may not be the "face" of the band, but you are still out there in front of people. Don't be afraid to go to the bar and rub elbows in between sets and at the end of the night. Love your fans and they will love you.
Odds are there will be atleast one bass player in the crowd that thinks that you're groovy, or is atleast nice enough to say so. This is a great boost and isn't just something that happens to guitarist and vocalist.
I really don't think that I can say enough to play the fans even when you're not on stage. The people like you, the more they talk about you. So, that guy that said "You guys are pretty awesome" and you bought him a beer, will go tell his friends "The next time these guys play, you have to come check them out with me." The more asses in the seats, the bigger the payouts. The bigger the payouts, the more gear you can buy. The better the gear and the bigger your fanbase, the better the dives you'll get booked. It keeps growing and growing.
Remember that even if you're an artist firstly, performer should be a very close nubmer two. I mean really, I know I'm not alone when I see a band at a bar then after the show/set go try and talk to the bass player. The guy is an ass. I never bother to see the group again.
Well.... /Public relations rant off