Don’t Use More than Two Typefaces

It’s a pretty common point of confusion, but typefaces and fonts are different things. “Proper” design professionals call them “typefaces,” while fonts are the files on the device that the software uses to display the typeface. Fonts are the paint on the palette, while the typeface is the masterpiece on the canvas.

For example, Helvetica is one of the most widely used typefaces, but a font is a particular set of glyphs within that font family: for example, Helvetica Condensed Bold, 10pt.

Regardless, too often designers add too many typefaces to their products. You should aim to use two typefaces maximum: one for headings and titles, and another for body copy that is intended to be read in depth.

Use weights and italics within that font family for emphasis—rather than switching to another family. Typically, this means using your corporate brand font as the heading, while leaving the controls...