Get Prepared to Communicate: physically, vocally and mentally prepared prior to your speaking event.
Find a private place to do a few warm ups (roll shoulders, shake out the nervous tension, massage your face, bite the tip of your tongue and count, say a few mmmmm’s, do the motor boat sounds, check your alignment). Try the posture that Amy Cuddy mentioned—open arms wide above your head. Another posture she suggests is standing with legs apart and hands on your hips—do it for 2 minutes. Tell yourself this is going to be great!
Amy Cuddy: Your body language shapes who you are