A while back, I posted this on the Graphene support forum. I want to expand on some of those points a little bit here.

I read a lot of forum threads where someone says “I tried that and nothing changed.” Occam’s razor tells us to try the simplest things first. If you change something, like custom CSS, and nothing happens, try the following:

1. Reload the page. Just because you close the page and reopen it doesn’t mean you’ve gotten the page from the server. Some browsers are very good about pulling pages out of their cache, even if you click “reload” or “refresh”.
2. Better yet, empty your cache and then reload the page. If you don’t know how to empty your cache, check the help menu or use the Google.
3. Disable your caching plugins if you are using them, because no matter how many times you empty your browser cache and reload, until the refresh time has expired, your browser will continue to reload the same html files from the server, rather than requesting that the server generate new ones based on the original php.In fact, until you get a lot of traffic to your blog, you can probably get by without any sort of caching plugin. You can use WebPagetest to see what your actual load speed.
4. Be sure to view your page in different browsers because not all browsers display things the same way, especially if you are running IE. What is often a problem in IE is not a problem for any other browser.That said, however, all browsers are a little different, with Safari and Opera somewhere in between Firefox and IE, at least with regard to how they display things.Additionally, because the new browser doesn’t have the old version of your page located in its cache, you’re getting a “fresh” version downloaded from the server.
5. You can also view your web page in a private window (which Google Chrome calls an “incognito window”), which will not pull a page from the browser cache.
6. Last but not least, be sure to click the “save changes” button before you navigate away from that page. It’s easy to forget this, especially if you are tired, frustrated, excited, or a noob. I’ve been all four things and I’ve forgotten to do this many times.

Hope this helps.