Listen to what's going on around you as you're playing. Listen to what the drummer is playing, listen to what the guitarist is playing and remember you are all playing as a band, not as individuals playing the same song. It's a team game. If you make a mistake, who cares, you cant go back and change it, it's done, it's out there. I bet you hardly anyone noticed. But most importantly, have fun! none of the guys that post on here would keep on doing what they do if they didn't enjoy it!