Keep the main point and the supporting points short and few. Focus on main ideas, not complete sentences. If possible, bring in the points one at a time and fade the points to a lighter color once they have been covered in order to focus the attention on the current point. Keep boiling down to the essential. The flowery and subtle have no place on a slide.
Slides support a presenter.
They do not replace a presenter. The slides are just the facts. Most presentation programs are full of special effects. They are sold by showing all the cool effects provided. Unfortunately, most first time builders try to use every effect available.