If you think a plain white background is ineffective, use a pale pastel color, or at most,a muted background pattern. Avoid loud patterns that distract the reader from the words and graphics of the text. 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.
Don't waste space by using decorative graphics, which don't convey useful information. Think hard before you use clip art. Instead of a large graphic, which takes a long time to download, use a thumbnail graphic. Then tag the thumbnail so that readers who click on it are linked to a large version of the graphic.