Avoid loud patterns that distract the reader from the words and graphics of the text. Use conservative color combinations to increase text legibility. The greater the contrast between the color of the text and the color of the background, the more legible the text. The most legible text is black against a white background. Avoid garish combinations, such as red text against a purple background.
Poor contrast affects legibility.
Avoid decorative graphics. Don't waste space by using decorative graphics, which don't convey useful information. Think hard before you use clip art. Use thumbnail graphics. Instead of a large graphic, which takes a long time to download, use a thumbnail graphic.