Fonts can be fun, but don't overdo it. One rule of thumb: Use a maximum of three different fonts per page. You should use minimally the varying font sizes. Too much variety can be jarring to the eye.
Avoid long stretches of text in italic, bold and uppercase, which can be more difficult to read than regular upright type. Similarly make sure there's enough contrast between the letters and their background.
Black on white is easier to read than white on black, and both are easier to read than green on blue. The most legible combination is black on cream.
Reid Goldsborough is a syndicated columnist and author of the book Straight Talk About the Information Superhighway. He can be reached at firstname.lastname@example.org or www.reidgoldsborough.com.