Excellent post with lots of great info! I've done a ton of presentations to tech audiences and have benefitted from the fact that in a prior life, I actually was pretty serious about theater :)

One tip I think is worth mentioning, is that while practicing a presentation (that doing it over and over in your office step) - video yourself and catch a glimpse of what's going on from the perspective of someone in the audience.

It's amazing the stuff you'll catch that's tough to identify even if you're presenting to a mirror.

One of the benefits of practicing a presentation until you've "got it down cold" speaks to a later point of yours. Once you've got it down, improvisation is *easy*. It's perhaps counter-intuitive, but having a presentation scripted and practiced doesn't pidgeon-hole you into a particular delivery; instead, it gives you some freedom because it puts you in a position where you can spend your attention on the audience rather than on the particulars of delivering your message.

-Mark