1) Tell a story. Most people are much calmer in telling a story than “delivering” a speech. So, if you start your presentation with an appropriate story, you’ll be less nervous and more confident.
2) Smile. There is nothing that you can do to the rest of your face that communicates more powerfully than a smile.
3) Create energy by speaking in a bigger voice. That doesn’t mean to yell, but to really speak strongly.
When you do your body becomes more animated. Your arms and hands more orchestrated. Your posture is straighter.
Practice these things in front of real people (not a mirror) and you’ll wow the audience when it counts.