Here's an interesting article recapping a presentation by Harvard Business School's Professor Dale Deletis. He suggests a strategy using the acronym "ABCD," where:
A = Articulate (prepare and practice out loud)
B = Bananas (eat bananas for potassium, which relaxes muscles)
C = Caffeine-Free (avoid the "chemically-induced hyper-state" produced by caffeine)
D = Deep Breathing (promotes relaxation)
There are also a couple of charts, one showing a list of potassium-rich foods, in case you don't like bananas, and another demonstrating steps for weaning oneself off caffeine! Check out the article for more on Professor Deletis' philosophy on reducing public speaking fear.