My suggestion is that you focus not so much on plot, the "whats" but explore the "whys" of what has happened in your readings. For example, what motivates a character to do what he or she does? If she steals, what has caused her to act outside of the social norms? If you see a recurrent image, water, for example, why is the author using that metaphor?
Be aware, too, of the use of similies which enrich the language and separate fiction (usually) from non-fiction.
Begin to trace a discernable theme. In the example you have given here, from "The Natural," one of the themes is choices and consequences, so be aware of that. For every choice a character makes, how must he pay for the choice, or how is he rewarded?
If you really have a difficult time keeping characters straight, I suggest you make a little list in the front of your book that you can flip too to remind yourself.
Hope this helps! :)