My favorite tip is No. 1: Think about your slides last. This is absolutely critical for any presentation, no matter how short or unimportant. I like to start with an even simpler question: Do I even need slides at all? Believe it or not, most presentations do not need slides. Period.
People attending your presentation are there to see and hear you. They are not there to see your slides. If all they cared about were the slides, they’d wait for them to show up on a web site and just download them.
The other tips on the TED blog post are excellent. Go read and do your part to make deadly PowerPoint extinct.