Your three rules are the problem, they result in presentations that are visually stimulating, but does not carry any information that sticks.

Such presentations are very simular to TV news. If you ask people after watching a TV news broadcast, they in general answer that they feel informed. But if you ask them about what was in the newscast, they remember very little.

PowerPoint presentations have the same effect, they give the subjective impression of being informative, but the audience learn very little from them.

Your advice are fine if you want to be popular. If you'd rather want to be informative, here are some better advice:

  1. Blackboards rule, if have the skills. But they require a lot of the teacher in organization talent, multitasking, and handwriting. For most people, transparents are better. Handwritten is best, if you can write so everybody can read it.
  2. The basis should be the oral presentation, the slides should support it by providing structure. This mean they should be mostly text, but not much. A good slide has 5 plus/minus 2 bullets (yes, it is cliche, but it works), each containing 1-3 words highliting a point in your presentation. Never complete sentenses, they are an aid to your oral presentation, not a replacement for it. Using handwritting helps avoid overloading the slides.
  3. A bit of carfully chosen color is fine. Avoid animations at all cost. Some topics will need diagrams, but remember, you can not actually present raw data in this form, only the conclusions and highlights. Keep the diagrams few, and if you have any drwaing skills, prefer handdrawn diagrams.
  4. You will obviously need to know what information you want to get across, and you should attempt the presentation at least once. But do not learn it by rote, unless you are an actor or other professional. For most people, a bit of improvision on the spot makes the presentation feel more alive to the audience.
Of course, if your job depends on a positive evaluation from the audience, or you are doing this as part of an entertainment gig, follow the other guys advice. The audience will feel entertained, and give you high marks (or suggest friend to hire you). My advice only pertain to the, perhaps rare, case when you have some information it is important to you to deliver to your audience.