A lot of the study I've done has been readings-based.

I take notes of most important points (incl page numbers) and underline key sentences, in case I want to go back and use them in an essay.

Then you can refer to the notes when you need to and only re-read little portions if you need to.

This works for me because I have a very visual memory. You might have an auditory memory (read notes aloud, get your hands on a text-reading program in your computer and use that) or a kinesthetic memory (map key points onto a mind-map so you get a spacial memory of "where" the info sits OR distract your body by chewing on something or moving about while you are reading). HTH