The visuals you use should introduce only the essential elements of concepts you'll discuss. The audience ought be able to get the point of the visual within the first 5 seconds after it appears. During that short period, don't say anything - allow the audience to absorb the information. Then, when you have their undivided attention, expand upon what the slide has to say.
For this approach to be effective, you'll have to include only the most pertinent information in each visual. You should limit the text contained on each visual and restrict the contents of tables or graphs to include only the information most pertinent to your topic. A common pitfall, particularly for those new to the possibilities of computer graphics, is creating artistic rather than useful visuals.
Once you've visited these pages, please RETURN to the 4 concepts page for more hints and suggestions.