I know I’m not the first person to suggest this, but I’ve come around to the idea (which was probably the original idea, anyway) that your powerpoint slides should ILLUSTRATE your talk, not BE your talk. I think everyone’s seen powerpoint presentations where the person just reads their own slides and has written an entire article on the slides themselves. So, without further ado:
1.) The slides should illustrate your talk, not BE your talk. You should never end up just reading your slides. Repetition for emphasis is an exception- if you want to get a short, concise point across by having them see AND hear it. You can only do that once or twice in a talk, though.
2.) Things on the slides should be things you don’t want to have to say, or further details people might be interested in. Things you’re going to explain verbally should not clutter the slides.
3.) Pictures and graphs are worth a thousand words. Don’t skimp on them just so you can say you didn’t rely on Powerpoint.
4.) Pick a few animation methods and stick with them. It looks more coherent if you don’t try to use all 50 ‘entrance’ animation methods. All of my Powerpoint slides are done with “appear”, “fade in”, “shrink/grow”, “rotate”, and “change color”.
5.) Make sure everything will appear fast enough to not hold up things. No one likes waiting for the noisy typewriter effect to type out your entire paragraph, letter by letter. (Actually, I think the typewriter effect has been gone for years- it’s not in Powerpoint 2010; I just remember as an undergraduate watching someone have to wait for, and then shout over, the typewriter effect.)
6.) If your figures are complicated, consider making several less complicated versions and then flipping between slides (or using animations) to gradually increase complexity. Show just the points, then re-draw the graph with the fit lines, then re-draw it with the one-sigma error ellipses… No one likes having a complicated diagram just shoved at them.
7.) Kill your darlings. You may really like the slide, but if it doesn’t have to be there, don’t put it in. Your fascinating side note is someone else’s unnecessary clutter. Remember, they don’t know the material as well as you do.