Rehearse the event in your mind as much as possible before you go on stage and see yourself performing well each time. The more you practice ahead of time, the easier it will be to do what you need to do automatically and the more confident you will feel.
Avoid eating heavy foods, such as foods high in fat, in the hours before the show or presentation. Physical discomfort from food, which can be exacerbated due to the excitement of the moment, will make stage fright seem worse.
Focus only on positive things. If your mind wanders to worrying about how you look and how you will perform, for example, you will fill yourself with doubt and increase the debilitating effects of stage fright.
Exercise before going on stage to relieve some of the anxious energy. Jump up and down backstage or do push-ups or even a little running. This helps work off some of the adrenalin caused by the fight-or-flight fear response. When you are through exercising, although you may initially be red from exertion, this will go away and may prevent blushing later due to nerves.
Take deep breath, inhaling and exhaling slowly until you feel calmer. Do stretching exercises to relax the body further.
Pretend the audience is made up only of your friends and family or use any other scenario that makes you feel more comfortable.
Make the energy of the stage fright work for you, rather than against you. Physical energy is physical energy--if you use that energy to liven up your speech or your performance, eventually the unpleasant sensations, such as trembling, dry mouth and blushing, may give way to more pleasant feelings.