1. When you sleep your brain reorganizes for long term storage. During the semester, you want to study, then sleep, and have your brain do its thing to store information long term. However, if you are truly night-before cramming, it's smarter to sleep from like 9pm - 12pm (90 minute increment!) and then spend 8 hours cramming and write your test without going back to sleep because you're short-terming it and need as little brain change as possible.
2. If you're getting tested on names/dates, and other specifics, all the studies show you're better off lasering your focus on a few key things you think your prof will put on the test and gambling on those being there. DO NOT waste your time learning general information on every unit. For a details-oriented test, you won't be able to score points if you only know the context and general information, so don't waste your precious few hours trying to conquer everything. Accept your situation, cut your losses, and be a laser on the things you think are going to be on there. This is where you poll your classmates and use their instincts to triangulate where you should focus on the details.
3. Invent and memorize a few mnemonics. Scan your mnemonics as late as you can until they tell you to put your materials away, and then repeat them to yourself over and over in your head as you wait for the tests to be handed out. Then as soon as you get your test, brain dump them on the first page. This is not cheating, it's just effective strategy.
For example, in music, you might memorize the order of sharps: FCGDAEB. "Father Charles Goes Down And Ends Battle." So first you brain dump a bunch of weird things like FCGDAEB on the page, and then you IMMEDIATELY decode them and write that down, because you don't want to forget the meaningfulness that you've attached to it.
Voila. A *legal, moral* cheat sheet.