Don't sabotage your own presentation.

Recently I had the pleasure of sitting in on an excellent presentation about aging. It was co-presented by two highly qualified, very experienced women – professionals in every sense of the word. They split their presentation time, each taking on half the job. The first speaker broke the three rules that I consider absolutely basic, beginner-level advice. The second one offered a polished, accessible, engaging presentation that was a pure pleasure to watch. So what were the three basic differences between these two presentations?