I'm lucky enough to not feel nervous about a show until the last possible second (as in right before I go on). I'm fairly comfortable once on stage and doing my thing. I'm not entirely sure if it's just me as a person, or if it comes from many years of Tae Kwon Do (my instructor loves to put people on the spot infront of alot of people). It's probably a mixture of both. Of course I have yet to face more than a few hundred people, so time will tell just how lucky I am.