How should I study for my English exam?

I have a final English exam this week and I have no idea how to study for it. It's going to be a commentary on one of five passages given from either Catcher in the Rye, Macbeth, or Animal Farm. I've read all three books but I have no idea how to study for this exam other than rereading the plots of each and making sure I know a good commentary structure. What else can I do?