In med school, I never studied that well late at night. I could never retain what I was trying to learn. I started this during my first year and it worked great. I would study my ass off until the day before a test (which we had every 3 days). The night before a test I would go to bed at about 6 o'clock. I would then wake up at about 1 in the morning and just review everything that I had already learned. That way, when the test came at 7 in the morning, everything would be fresh in my mind. Doing it that way, my average scores went from mid 70's to upper 90's. Try it, it might work for you.