There has been a lot of criticism about the way TED talks are presented. A lot of that is warranted and I am not seeking to defend them. However, Chris Anderson, the curator of TED, talks about how the talks are put together.
Here is the surprising thing: most of what he says is preaching 101. But it is good to hear again because we forget the basic principles of communication. What are you basically doing when you preach? Take 8mins out to remind yourself again. If you are really lazy then jump to 5:05 for the 4 key points.