Sip some water before you start so you don't have a dry mouth.
Take a few deep breaths before you start.
Deliver your presentation standing up - unless there is a good reason why you can't.
Remember to smile. You want your audience to feel relaxed and engage with what you're saying.
Make sure you look around the entire room. (It's easy to exclude people if you focus on the most senior or influential person in the room)
Don't speak too quickly
Keep still. Rocking, excessive flapping of hands is distracting.
Don't use any kind of joke unless you are supremely confident of pulling it off.
Sound enthusiastic and passionate about the subject.
However nervous - Try and enjoy it!