[TeMPOraL]

Lots of good advice here. I'd add:

- Ask yourself what is your real goal of the talk. Are you trying to teach people something? Or are you making a live-action advertisement for a product/service (or for yourself)? Optimize your talk ruthlessly for that goal.

- If you're doing a talk in front of a small audience (say, 30 or less people), and you're going to discuss details of code or charts presented on slides, then put all those code snippets and charts you want to discuss in a single document and give everyone a printout. A printed document has much higher resolution and quality than a slide (especially for the people sitting in the back), and will allow them to look back (or forward) at an important figure if you're currently showing another slide. Paper is cheap and quite ecological, so don't worry about that.