Choose fonts that are appropriate for your subject matter and overall design. For example, don't use a goofy, decorative font for a corporate presentation; instead, choose a modern-looking sans serif font.
Select a font color that contrasts with the background color in terms of lightness, if readability is important. A font that is colored too closely to the background will be difficult to see at a glance. The exception to this is if a watermark look is desired, and readability is unimportant.
Space lines and letters evenly throughout each body of text. Having uneven spacing will not only look unappealing, but it will also confuse the reader, as he has to keep guessing where the next line will come.
Add white space wherever appropriate to let your text breathe. Too much text with no space will look and feel crowded to readers, while white space gives their eyes a break.
Organize type on the page or screen using grids as a guide. Grids help keep typography lined up, and can be used to pre-visualize the overall layout of text even before words have been decided on.