I read an interesting technique for improving presentations: 1. Create an outline, then record yourself pitching freeform from the outline. Practice many times until you get a recording that seems perfect. 2. Then, memorize that recording WORD-FOR-WORD, until you can deliver the "spontaneous" pitch with perfect timing every time.

I can't find the source right now, but I'm pretty sure it was an interview with Donovan Brown talking about his presentation technique @ Microsoft.