ONE: Practice. Practice to the point you almost don't have to look at your notes. Practice looking up. Practice pushing the advance for your next slide. Practice walking to the front of the room. Practice smiling. Yes, you must practice all the details that you want to happen because once there's someone watching, everything tries to go wrong. Not everything will but nerves get in the way. Just so you know, those who do improvisation, practice. Oh, they can't rehearse every thing an audience might throw at them but they practice the games over and over. It takes a lot of practice to act natural.
TWO: Pretend you're not scared. Or nervous. If it makes you feel any better, we get nervous right before EVERY show. Every show! You'd think we'd get used to it. Yes and no. We get used to being nervous! But we don't let it stop us. Don't let fear stop you either. Make sure you practice a lot, then pretend you're not scared. After you're done and no one is around to see you, then you can sigh, wipe the smile off your face, and empty your stomach if you have to.
Break a leg!