Hi, Kris. go to the pub early, and play with the mic. There are a million variables. The best luck will get you a sound man at the gig. then you can sing and he'll make it sound OK out front, and you don't worry about it at all. If there are stage monitors, you can hear what you sound like.I didn't think they made much difference in smallish places, but I was wrong. Don't wait untill showtime to try out the mic. Some pick up from quite a distance, and some from only a couple of inches. Both good, but real different. Talk a little. Tell a joke and see if they laugh in the back of the room. That would probably mean that they heard you. When you find a good distance from the microphone, measure it. One hand span? A hand and three fingers? This way, you won't get lost. If you mislay your spot, you'll know right where to find it again. Maybe Mark could coach you during the performance from out front. A hand cupped to an ear to call for more volume, fingers in ears if you're too loud. Fresh feedback is the best. Maintain the dynamics you've practiced with your friend, the PA will do the rest. If you practiced loud, perform loud. Once you've got the system where you want it, try to forget it and play as if you were at home. Ignore noisy people. In fact, if they make you nervous, ignore everybody. When I wish everybody would disappear, I take my glasses off and they do! Break a leg(bad luck to say "good luck" before a performance, y'know}.