You should be paying attention to the following five things. First, look at font size and type. Keep in mind your audience is typically frather away so you need to be sure the audience can see your presentation. Second, may sure you use short, concise labels. Third, use consistent backgrounds. Make sure your images and backgrounds don't take away from the flow of the presentation. Fourth, use good contrast. This is especially important when using images. Be sure that the content is easy to read. Finally, be sure you are using high quality images. Don't ever use clip art.