I think something you need to consider is to use design tools for designing - paper and pencil, then gimp/photoshop.

The best designed sites out there aren't designed on the web, but rather designed for the web. Try to make a good design first and then use your html/css skills to adapt it to the web (and obviously since you know the limits of html/css you can keep yourself from going to far in a direction that would be overly complicated to implement).

Also, keep it simple to start and make incremental changes.