Be sure to choose a theme with good contrast and with simple backgrounds. Some of these templates have low contrast between slide text and the slide background, and a few may also have busy backgrounds that can make text even more difficult to read. The Design tab contains many built-in Themes and color Variants that can be used to change the look of a presentation, as well as the ability to create custom themes The first step in creating a PowerPoint presentation is choosing a slide theme or template.