You don't want to eat too close to the time you will be on stage, and you don't want to be hungry and faint the whole time you are there. A healthy, well-balanced meal that includes a whole grain and a protein source one hour before you go onstage will supply the energy your body needs to give a great speech or performance. Avoid alcohol, caffeine and sugary sweets, which can make your blood sugar spike and your anxiety increase.
If you are giving a speech, make sure understand your topic thoroughly. Know the questions that might come up in a discussion and write down the answers you would give to those questions.
Actors can calm stage fright simply by knowing the lines well. As your confidence increases your stage fright will decrease.
Long, slow breaths will give your brain the oxygen it needs to keep functioning, and to keep you from passing out. People with stage fright often forget to take normal breaths as anxiety builds up. If you feel stage fright coming on, stop and take three slow, deep breaths. Repeat as necessary.
Use your home mirror to practice your song, your lines or your speech. Look yourself in the eyes and try to talk just like you will when you are in front of the audience.
Ask people who care about you to join the audience, or ask them to serve as an audience for one or more practice sessions. Their support will help relieve the stress of stage fright.
Clothing that is too tight or too hot can set you up for great discomfort if you begin to panic. Often stage fright will start with hyperventilation and an overheated feeling. Wear lightweight clothing to prevent such problems.
Instead of looking directly at individuals in the audience during your performance, look beyond them into the back of the room. This will give audience members the feeling that you are looking at each of them without the need for direct eye contact.
If you still feel that your stage fright is more than you can handle, it is important to ask for help from a person you can trust. Your director may be able work through your stage fright with you before the next performance.
If all else fails, remember that your speech, song or play is not the end of the world. Minimizing the grandiosity of the experience can help minimize your stage fright. You have probably been at the center of attention in the past, as when your name was called at graduation or you opened presents in front of your family, and enjoyed it. Concentrate on making this performance more about fun and less about worry.