Getting drunk before a gig is such a bad idea. Performance anxiety is natural. But once you get like five minutes into your set, you forget the audience even exists (or at least I do). I'm very calm and relaxed on stage. I kind of go into a 'zone'. The more you play infront of people, the easier it becomes. Do little performances for your cat, your dog, your parents, and friends until you don't even notice they're there. I always remain calm before hitting the stage. If you let yourself get worked up over nothing, it will be apparent in your demeanor.