That’s been the question on my mind ever since I tried to write some CSS and it was terrible! Here are some of the things I’ve been reading.
Maintainable CSS – a guide to using semantic HTML, combined with not trying to write reusable CSS, in order to make modular styles that can be edited without causing problems elsewhere.
Learn Layout – a very clear tutorial on how to position elements on a page.
BEM Key Concepts – I’ve been starting to get my head round BEM (Block, Element, Modifier) as a way of organising styles. This ties in well with the Maintainable CSS piece, above.