1. Don't try to write jokes into the presentation. It won't be funny. It will only be funny if the joke comes to you on the spot.

2. Try to write the talk in terms of vague concepts instead of specific wording. WHen practicing, don't worry about how you're going to express a certain concept, just focus on understanding the concept inside and out. Every time I give a talk, the words come out a little bit differently each time. This keeps the talk from sounding robotic.