[A] PowerPoint presentation should have ten slides, last no more than twenty minutes, and contain no font smaller than thirty points.Oratory - rather than wording on slides - dominates the most effective presentations. Kawasaki explains:
The reason people use a small font is twofold: first, that they don’t know their material well enough; second, they think that more text is more convincing. Total bozosity. Force yourself to use no font smaller than thirty points. I guarantee it will make your presentations better because it requires you to find the most salient points and to know how to explain them well.If you find your product manager's presentations dry or unfocused, make her aware of the 10/20/30 Rule of PowerPoint.
UPDATE: Seth Godin reminds us of his advice about PowerPoint presentations, which meshes well with Kawasaki's advice.