With text, always err on the side of large. It is a good rule of thumb to keep each slide in a presentation simple. Too much information on a slide can be difficult to assimilate quickly and may make a presentation hard to read. When developing course notes, break materials into small, digestible chunks of information. As a general rule, if a slide's text cannot adhere to at least a twenty-six point font size, the slide should be broken into smaller pieces.
Backgrounds Try to keep the background images in a presentation simple, as well.
A complex, multi-colored, or bright background can be distracting and may render the foreground text difficult to read. Simple gradients of dark colors, solid colors, or simple, subdued patterns work well as backgrounds. Graphics Clip art and graphics should also adhere to the principle of simplicity. Limit your color palette, and limit clip art to a few appropriate images per slide. Graphics and charts should use bold, thick lines, and all associated text should follow the font guidelines explained above.