There is no "quick and easy" way to study - you have to train yourself and your mind like an athlete.
If you want to remember a story, then make notes as you read on the plot. To help understand, you will need to do secondary critical reading. Even using Cliffs Notes is a form of secondary reading.
As you start developing techniques, you'll learn what works for you and what doesn't work. There really is no other way besides hard work.