Principles of Legibility: A Guide to Not Being a Clueless Cliché

Rule 1: Use a font size larger than 10pt. Don't be a hero, be legible.

Rule 2: Avoid using Comic Sans. It's not funny.

Rule 3: Use sufficient line height. Don't cram words together like a sardine.

Rule 4: Use sufficient leading. Don't make readers squint.