Thinking about the markup before the styling

It's easy to reach for a div before thinking about what you're building. I do it too. Then I look back at the markup and realise I've described almost nothing about the page.

A heading should tell you what follows it. A list should group related items. A button should do something. These aren't difficult ideas, but they deserve a few minutes before the styling starts. Reading the document without its stylesheet is a decent way to spot where the structure has gone missing.