Am I the only one who loves that phrase? Even if so, it's compeltely true. I find that whenever I get stressed out, especially during midterms or finals week (or those weeks where all professors give me three thousand things to do) that there are at least two things that help me stay calm: a clean desk and yoga. Let me explain:
Keeping a clean desk: In order to stay calm, having a clean desk and clean surroundings always helps. Try and keep a calendar with all of the deadlines you have, any to-do list and organize your desk every night. This helps to make sure you won't miss an assignment, or lose a paper (trust me, I've done it before. Not fun). Keeping a clean space will help you stay relaxed and not stress out.
Yoga: Try it. Trust me. It is SO relaxing. Just take a 10-15 minute break from homework and do a few yoga poses. It will help you feel so much more invigorated and so much more relaxed. It's been shown that inverting your body so that you pelvis is higher than your heart is very tranquilizing. Don't forget to breathe deeply!