Getting your styles right
Styling done right in Drupal means you need to style the system, not individual pages/designs, allowing for a DRY set of styles which keep your site lean and mean. But it can be difficult to find all UI elements which are used throughout Drupal. A handy module which makes this a lot easier is styleguide. It renders a page with all core style elements, buttons, tables, lists, forms and whatever you have, making the life of a themer that much easier. Oh, and by the way, did you see the Drupal 8 proposal for the Seven theme style guide?