Here are the questions I ask after I write CSS:
- Did I match the design?
- Did I repeat code?
- If there is repeated 'positional' code, can I extract that out into a 'class' and immediately start using that class safely?
- Did I target the elements I'm interested in appropriately? i.e. not too specific, not too broad, not tied to a tagName unless there's a good reason to do so.