It's inevitable that you'll feel some nervousness before going onstage or waiting for your turn to perform...that part is the killer. Worse if got good bands playing before you *lol* But once you got onstage and the playing starts, treat it like a jamming session, make eye contact with your fellow members and not worry about the crowd at all...
Once you have some experience in gigs, etc, you'll grow to love to perform in front of an audience...that is when you can work on your showmanship more...like making eye contact with audience, moving around, grooving with the beat, and interaction with the audience, etc....
In time to come, you'll get to the stage where you'll get excited and thinking about ways to wow the audience...or just indulge yourself in the playing totally and don't care for a thing in the world...hahah...
All in all, the more places/gigs you've played, the less nervous and more settled in you'll get. Of course, there'll be exceptions...hahah...I do get a bit overwhelmed once in a while even after playing over 20 gigs :lol: