Step 1: As early as possible, know your content up one side and back down the other.
Step 2: The morning of your program, take your mind totally off your presentation.
Step 3: Before your program, listen to whatever you can to make yourself laugh intensely. Laughter fills your blood and brain with good chemicals that make you feel great, relax you and put you in an awesome mood.
Step 4: Nerves are normal. Don't worry about them.