Take control of anything you can control: this creates a natural sense of comfort
Dress comfortably: most IT events are pretty casual, so…
Dress for the weather: shorts, sweater, etc.
Be mindful of caffeine – don't ramp it up just for your presentation!
Caffeine heightens senses, and makes you more anxious, not less
Use the restroom right before you go on
Put your phone (and notebook) in airplane mode so you won't be disturbed