Juan Pablo de Gregorio has a very interesting article about 15 things to keep in mind when choosing a text type/font.
In addition to what he’s mentioned, I keep these things in mind:
- Sans-serif for headlines and titles, serif for body copy, or vice versa
- Visually separate headlines/titles and body copy in more than just text size and decoration/weight. The reader will be able to pick out headlines/titles quicker.
- Some fonts have a very, very high line height. While whitespace between lines of body copy is very important and visually pleasing, too much can make the text seem too large or indicate that there was an error in printing or layout. Most desktop publishing programs (and CSS, too) have a way to adjust line height. As a rule of thumb, I use a line height one-half point larger than the size of the text for body copy, and the same height for headlines/titles.
- Pablo de Gregorio does mention it, but I’ll add a bit. For newsprint (not necessarily for the web!), it’s beneficial to adjust the kerning so that the letters are almost colliding. This saves paper space! It’s amazing what a kerning of -1 or -2 will do to text, allowing for more room on the page for text. However, keep it consistent–don’t adjust per paragraph or article, but use a standard style throughout all of your body copy that keeps things the same everywhere.