Here are a few pointers, garnered from a couple of old stage hounds, about how to get through your first few experiences playing in front of other people.
1. Know your material
Practice your songs, in front of other people if you can, to prepare you. If you cant, practice in front of a TV (w. sound on at a low volume), will get you used to distraction of being on stage. If you dont know your song by heart, then its OK to use sheet music/ words: Bring your glasses, if you wear them, and print out the words and chords large enough to see them. Also, bring a music stand if you dont know if the venue has one or not.
2. Prepare your instrument & equipment
DO NOT put on new strings the night before you perform! Tune your uke fairly shortly before its your turn to playin case temperature/humidity have changed it, and do bring extra strings, just in case. If youre using an amplifier, effects, your own mics, etc., set up things EXACTLY the way youll use them on stage. Then, pack all those things directly into your bags and car for transport to gig (less chance of forgetting things that way). Bring extra cords if you dont know what the venue has on hand. You should even practice while wearing the shirt/blouse youll wear when you play (sleeves, slippery shirt materials can cause problems).
3. Sing & Play into the microphone
If youre playing on stage, first of all, find a comfortable position to play instanding or sitting, then adjust the position of the instrument mic to point at or near the ukes sound hole. Set the vocal mic to a comfortable height, pointing a little to the side of your mouth (to avoid popping). Dont be afraid to sing CLOSE TO THE MICitll make your voice richer and fuller. While you play, dont move around too much, and if you use a music stand, make sure you can see it without craning.
4. Play through the song
If youre nervous and you forget a line, play a wrong chord, etc., DONT STOPjust keep right on playing. People often wont noticeor care. If you go blank and forget a whole bunch chords, just keep strumming while damping the stringsto keep the rhythm of the song going, then jump back in at the beginning of the next verse or chorus. If you have a real train wreck right at the beginning of the song, dont be afraid to just stop and say Lets try that again Itll usually draw a laugh and release the tension. Above all, try to have FUN when you perform; people would rather see someone who has fun and flubs a few chords than someone who is a virtuoso but is really uptight !