Have you ever noticed that you work better in some places versus others? Studies repeatedly suggest that people are more productive when working in environments of their own design.
Now that finals are upon students everywhere, ask yourself if your space is optimized for effective studying by considering the following factors:
Later, my roommate's brother decided to really challenge my sanity by sneaking in before I returned from winter break and throwing my books all over my desk. He gleefully watched as I tried to stifle a panic attack.
So - my point: it's not important if you like things perfectly perpendicular on your desk. Rather, take a minute to weed out anything that is just taking up space. Empty soda cans. A notebook from last semester. A year's worth of magazines from that title you never subscribed to but keeps showing up.
Simplify what's in your space by reducing items down to what you actually like, need, and use.
A Room With a View
If it's possible, set yourself up near a window. If your view is a brick wall or something similarly uninspiring, find yourself a poster or print a picture of a scene you find calming - the beach, the mountains, New York City, whatever.
Tack the picture up at eye level. Enjoy.
Sit Up and Stand Up
If you have the option, adjust your desk so that it's more ergonomic; set the screen at eye level to avoid neck strain from tilting your head down and a chair that supports a straight spine.
It's great if your space allows you to move a little too for periodic stretch breaks. My home office, which is presumably comparable to the size of most people's dorm rooms, allows me to workout in front of the computer. Even if formal exercise isn't your thing, at least stand up and stretch for a few minutes every hour. Activity can be as reinvigorating as a cup of coffee, without the extra dose of caffeine.
Get headphones if you must listen to music and your roommate can't stand any noise when studying.
Consider ambient noise if you find music distracting but don't like it too quiet. You can either set up to work in a relatively uncrowded library, coffee shop, or study room. Or you can use Simply Noise, which just plays that fuzzy sound a radio makes when there's dead air.
Take it from the lady who had an ulcer by age 24. Cool it with the coffee.
As for food, it's up to you to figure out if you work better by eating a meal before sitting down to work, or having food on hand so you don't need to leave your desk. I'm not a registered dietitian, so I won't presume to give you advice about what precisely to eat. But I will suggest that you pay attention to how certain foods make you feel.
If too much sugar makes you fuzzy-minded and lethargic, skip it. If a bag of Cheetos makes you feel like Michael Phelps going for the gold, I'm ok with that.
I understand your performance might be mostly motivated by wanting a good grade on your final exam, and, in some cases, just needing a C- to pass. But it's within your power to streamline your work space so that your studying can be a little more bearable and infinitely more effective.