Practice for your appearance in a relaxed and enjoyable atmosphere with people you feel comfortable with. Rehearse until you are confident that you won't make any mistakes.
Sleep well before the day of your stage appearance. Ensure that you rest for a sufficient number of hours.
Eat sensibly on the day you go on stage, avoiding stress-inducing alcohol and caffeine. One symptom of stage fright is the shutting down of the digestive system, so find the foods that are problematic for you and avoid them. If you are speaking or singing on stage, avoid milk as it causes phlegm. Keep blood sugar levels high by consuming plenty, even if you don't feel like eating, but don't eat too much sweet or heavy food.
Take vitamins C and B, calcium and magnesium supplements to calm nerves, reduce stress and increase energy. Check the side effects of any prescription drugs you are taking to ensure they will not cause you additional stress.
Exercise the night and morning before you go on stage. Walk briskly to get rid of any excess energy just before your appearance.
Take deep, meditative breaths. Stretch to relax your muscles and make yourself laugh to relax your mind.
Wear something that you know you look good in and get a haircut or manicure. Treat going on stage as if you had a date.
Close your eyes for a few seconds, while you're performing, if you are musician. This will create the impression that you are very absorbed in your music.
Move around to whatever extent you are able. Standing completely still tenses your muscles, tiring you quickly. Movement gives you the appearance of confidence.
Become absorbed in what you are doing. Ignore the audience and focus on your own act.