There are two aspects to preparing a talk: the content and the presentation. I like to keep the preparation of those two parts separate. It’s kind of like writing: instead of writing and editing at the same time, it’s more productive to write any old crap first (to get it out of your head) and then go back and edit—“write drunk and edit sober”. Separating out those two mindsets allows you to concentrate on the task at hand. So, to begin with, I’m not thinking about how I’m going to present the material at all. I’m only concerned with what I want to say.
A good and timely outline here as I begin laying out some ideas for a talk in November!