That's a tough one. I wouldn't blindly memorize the text but rather do the problems and find out what you don't know from the problems and study what you don't know. The only subject i can see you memorizing is certain aspects of biology, like clasification. You must also be cautious how you do the practice problems as well. A laid back , and "pratice" will not do much. But rather do them in the most ralistic possible way and then when you do a problem try to understand/ account what you have learned from it and go on to the next. This way you don't repeat the same mistakes. And of course time, the more problems you do the more comfortable you'll be with time.
Good luck