I posted the link below, which leads to a delightful guide to typography by Pierrick Calvez, about five years ago. But the link is still good, and so is the advice, so I’m sharing this again .

Click the screenshot (from a section representing “contrast”) for the five-minute guide.

Screen shot from Pierrick Calvez's Five-minute Guide to Better Typography

Screen shot from Pierrick Calvez’s Five-minute Guide to Better Typography.