Helpful study techniques for the 'rest' of us?

(by the rest of us, I am referring to those without amazingly high retention abilities such as photographic memory!)

Hey everyone. I'm curious to know what helps you comprehend and retain all the knowledge that you have and will continue to acquire. Now, I have no delusions of instant, miraculous results -- there are no short cuts when it comes to learning, I know But, I am always open to making my study times more efficient and productive and would love to hear what has worked for you.

I've listed a bunch of questions that I have, but please feel free just to say whatever advice or experience you can. Even if it's a book that you can recommend, I'm all ears.

THREE QUESTIONS ABOUT STUDY PRODUCTIVITY:
1) How do you approach and study new subjects or information?
2) How do you review / remember what you have learned?
3) What has helped you to build stamina for those long study hours?

I'm a post-bacc'er who currently works full time while studying to retake my prerequisites. Right now I put in about 2 hours at night during the week and most of the day on saturday. It's going well, but I would like to be able to process information quicker, and retain it better. It takes me several hours just to get through a chapter in my Orgo/Bio book before I understand and retain it (or most of it).

Looking ahead, I see even more knowledge to digest and absorb. And even though I'm psyched to pursue it, I also want to train my mind and its focus so that I make the best use of time.

Thanks in advance for your posts!