Use two typeface families maximum. OK, maybe three.

Choose typefaces for specific purposes. In doing that, you'll need to define what the purposes are, and you're likely to find that there are only two or three purposes for text in a project. Because a change in type family usually signals a change in meaning or function-restrain yourself!. A single type family with a variety of weights and italics should be enough all by itself; adding a second is nice for texture, but don't overdo it. Too many typefaces are distracting and self-conscious and might confuse or tire the viewer.