You could try some interview questions, plenty on google, as LL about algorithms, they will take you through core programing principles you would learn on a CS degree like data structures, lists, sorting (the big O notation) and tons of other algorithms. Graphics is generally maths(well rendering is if that's what your talking about) and applying your language to that. Or if your doing UI stuff like menus, dialogs boxes and all the controls most people use a toolkit like QT, gtk etc...
https://www.google.com/search?q=prog...sm=95&ie=UTF-8
This is a google search that might be relevant to your needs.
Keep in mind, I think most programming interview questions are BS. Not that they aren't important. They are so make sure you do some. But don't spend all your time doing them. I think making big projects work is just as important if not more so than solving some obscure problem with arbitrary conditions attached. But that's just me being bitter. Balance your education, basically.