First thing I am doing is scheduling my workouts and what I am doing in each workout (long run, short run, lift weights, spin, stairs, and/or yoga) into my iphone calendar. Making my workout as a scheduled part of my day as either a study break or a way to wake myself up in the morning will remind me that I really need to fit it into my routine. Because I don't have classes to work around, just exams and study/writing time, I can actually plan my study schedule around my workouts.
Next thing I am doing is avoiding grazing on snack food throughout the day, I am making sure I don't carry any snacks with me except for fruit, this forces me to get up out of the library if I really need food and to use meals as a productive break from studying. I am also making sure to eat breakfast so that I can power through my day from the start! Also keep a bottle of water with you and make sure you drink it (especially if you are drinking tea or coffee which will dehydrate you.)
As far as sleep is goes... I have no real ideas, it will depend on how productive I can be but I am aiming for at least 5.5 to 6 hours of sleep a night. I have yet to pull an all-nighter in college and I would hate to do that now. If there is a night where I can actually sleep a little longer than that then I will take full advantage of it, but don't think that you can recover from an all-nighter by sleeping 12-14 hours the next night, the body doesn't work that way for most people. Six hours of sleep is supposed to get you through two REM cycles which is actually pretty productive sleep. To get the most out of your sleep, don't eat right before you plan to go to bed, give yourself at least an hour, also stop drinking coffee or tea at least 3 hours before you plan to go to bed. If I can stress this any more, don't pull an all-nighter, try to get an hour of sleep if you can because your mind needs a little bit of rest, especially since its takes a lot of brain power to get through exams.
For my mental sanity I will take a break every two to three hours and talk to my friends or somehow communicate with the outside world! Do this especially if you have to study alone, like in the lonely little cubicles. Seriously, not talking to people will drive you crazy and breaks are essential, I know very few people who aren't taking ADD meds who can be fully productive for more than 3 hours, whether they get distracted by facebook or emails or they need a refill or to go to the bathroom. Give your mind a break and save your mental sanity!
Those are a few of the things I'll be trying to do from now (this is a study break for me!) until next Friday. I hope everyone has a productive and sane exam period! Good Luck!