Look at blogs for ideas. Blogs are good sources of investigating CSS, just browse through blogs, and if you find a good looking one, analyze its source.
For c++, get the IDE, and whatever your interest in C++ is, practise on it... for example you can be interested in web-based apps, or core windows applications or MFC or CLR etc. Forget about the visual studio 6 etc and concentrate on 2008, thats the latest, and thats what people in the industry care about.
Yeah, blogs are a great source for CSS. I completely agree. But doing CSS is just a kind of a leisure activity for me. I don't think I would be pursuing "web designing" as a career. Its basically a hobby and enjoy working on it.
I also like programming in C++. And I was planning to make a project based on development rather than designing. So, I basically need to find and implement ideas. Maybe a webapp, and in the process, I could learn something new like AJAX or Ruby On Rails. At this point of time, I have only done development of console based applications in C++.