If you get stuck on a concept, don't read only one book to try and learn it. Look for other books. Sometimes, some of the most subtle changes in presentation can help give enough perspective to get the crucial insight required to really grok a concept. The internet is awesome nowadays; alternative reading material is now easily obtained.
I had of my most influential insights from textbooks written in the 1970s (my undergrad days were in the 1990s), from the university library, which I decided to read out of curiousity curiosity when I procrastinated there. (Needless to say, my choice to procrastinate at the university library was made before the advent of widespread reading/writing of blogs as a means of procrastination.)
