I just saw this one on on scienceblogs.
It is a bit bold of me to put it up here after I've just recently put up two of my presentations here, but still...
I don't think I'm that bad at presenting, but I do tend to put too much on my slides -- and too much text -- when I am in a hurry with them. When I have plenty of time, I try to rely solely on figures, but as the deadline draws nearer, I get stressed and I use text instead of figures ('cause text is so much faster to put on the slides).
To the advice given in the video, I'd like to add one of my own: when you prepare a presentation, start by thinking about the story you want to tell. You need to have a story to tell, otherwise you won't be able to structure the talk, and you certainly wont give an interesting talk. Just listing results gets boring fast. If you have a story to tell, the presentation almost prepares itself. You don't have to prepare so much, because you can easily remember your story (but not as easily remember a lot of key points) and if you have the story in mind when you give the presentation you feel the flow of it and you are less likely to get nervous.
At least, that is how I feel it.