Well I would simply learn something by drilling it into my head. The reason I ask this question is that sometimes I find it difficult to remember the concepts when I am trying to solve a problem, as if everything just flew out the window. Thus, obviously it is hard to interpret problems when you don;t have any knowledge of the concepts in your head. Anyway, I wanted to know things like if people used flashcards for equations, read their notes a bunch of time, etc..