Yeah I'm using Quizlet and they are great; they also have an app that syncs with your account so you can use them on your phone as well. I have a mix of some cards with a single concept, and cards with the concept and some other important details (But as Ari said, you don't want to put too much info in a single card). I would also make cards with a specific question on one side and the answer on the other. It definitely depends on the person, but I find flashcards VERY helpful. I won't have time to make flashcards on all the bio chapters, so I'm doing them on anatomy, which is my weakest one. I think the mere fact that I am typing the information/concepts, helps me tremendously to solidify the info in my brain (it would be best to write them down, but again I don't have much time). For some reason, reading only something that I have never taken a class on before like anatomy, does gives me a general understanding of the subject, but does not help me remember all the small details/weird names.