I am no hero in coding, just happen to know where to look for the code to change and I do so accordingly. For HTML it is really easy. When I got into touch with CSS, it was a different story. Having played around with editors like StyleMaster it started to make sense, but still, I could not say I understood CSS.
So I decided to buy the CSS Anthology via SitePoint. Call it the bible or codex, it really is what opened my eyes and made things clear, in an understandable language. Think that for people with no background in coding this can really give the needed insight.
At the moment, I work even more efficient. FireFox’s Web Developer Toolbar gives the ultimate solution: WYSIWYG CSS editing! Wow. This really simplifies finetuning your website’s theme…
While visiting your own site (or someone else’s, just for good ideas of course) you can get all information on how the CSS is compiled and even change it, to see what it effects. For me it really eased the process of flipping the sidebar (default on the right side) to the left side.