PowerPoint Ninja is essential reading for improving your technical PowerPoint skills.
The most recent post is about embedding non-standard or custom fonts inside a PowerPoint presentation so that you can be 100% sure your presentation will come out as you intended it when using on another computer. Custom fonts are a major untapped designer resource for PowerPoint presentations. Over the past years people started using a number of graphical tools in PowerPoint. First enabled by technology, then "abused", after which a "Zen-oriented" tribe of people developed the common wisdom about how to use each of them correctly, elegantly, and most importantly in such a way that it helped the purpose of the presentation
  • Bullet points
  • Colors (my pre-2002 presentations were almost all B&W)
  • Clip art
  • Boxes and diagrams
  • Animations
  • Images: Google image search, stock images
I think fonts and typography are next.