February 22, 2010
Rule of Thirds -- the focus object within an image should take up about one-third of the total space being viewed; it should be centered along lines to which which the eye instinctively gravitates. So give some thought to what, exactly, you want your audience to see because the combination of whatever it is that you're saying along with your visually sparse (and therefore beautiful) slide will drive that point home much more effectively than something so busy it causes retinal fatigue that will literally put your audience to sleep.
Don't be afraid of blank space. Don't read your slides out loud; use them to underline a few key concepts and keep the focus on the speech you make. The slides supplement the speech, not the other way around.
Hat tips for bad powerpoint slides to Tim's Blog, ThugMed, and Neurodiversity. And of course to Dilbert for the comic.