A book that changed my way of presenting on stage is "Talk like TED" by Carmine Gallo.

Given nobody is expected to give a TED Talk, it can be inspiring and guiding.

The book gives valuable advice (some already given by others here) I try to summarize here:

• your role on stage is to inform, educate, and inspire
• be genuinely passionate about your topic, you'll inspire your audience
• don't be afraid to share your excitement about your topic, to inspire others you have to be inspired yourself
• tell a story to connect with your audience: stories illustrate, illuminate and inspire
• apply the golden rule of the three Ps: Practice, Practice, Practice!
• try to share new information or new ways to solve old problems
• surprise your audience, do something remarkable
• be likable, engaging, and entertaining; use humor
• create a Twitter-friendly headline for your talk, the main message your audience will remember
• apply the rule of three: people can remember three pieces of information very well; split your story into three parts

I warmly recommend reading the book to have the complete idea of what the above mean.

Cheers