A couple of useful things about giving presentations:
Michael Lopp, in his essay, The End, which you should read:
With their attention in hand, you need to change perspective. What was the point of this speech, meeting, or article was yours — now it needs to be theirs. A good ending is a selfless act where you put everything important squarely in the audience’s lap. Whatever your point was, it’s now their point, their lesson, their view of the story. The invitation is a question: “How can I make this theirs?”
Furthermore, Merlin and Dan talked about presentation culture and how to not “bomb the deck” in the latest episode of Back to Work. It’s really good. Read/listen so your next PowerPoint doesn’t totally suck.