Remember to keep it simple--
TIP: Write your last slide first - if you don't know where you are going, it is unlikely you will be able to get there. Plan your conclusion first; know what you want to convey. Make the rest of your slides lead to and support the final result.
TIP: To keep an audience focused, use dark colors for background and lighter colors for text and illustrations. The eye is naturally drawn to lighter areas and lighter and warmer colored objects appear closer than dark objects.