This guide is based on chapter 5 from the book Better Web Typography for a Better Web by Matej Latin. The book consists of 13 chapters through which the reader designs and builds an example website.
Bad typography on the web in the early years of the internet was often blamed on the poor range of fonts available. But we already learned that typography is not merely about choosing fonts. One of its goals (probably the main one) is presenting information in a way that is readable and easy to consume. Before we start looking for a font to add to our design and combine it with our body text font, we need to ask ourselves: do we really need more than one font? Don’t just add one for the sake of it. There’s no rule in typography that says the more fonts used the better (the contrary is probably more true). There’s no guarantee that adding another font to your website will improve its typography. I like to keep my typography simple and solid. Like a machine—the fewer movable parts, the less likely it is to break down.
... read the whole story at betterwebtype.com.