I can hardly call myself an expert when it comes to avoiding stress, but here's my personal tip.
However, as silly of a statement as this may seem, it is important to remember to breathe and to relax. I've learned from experience that stress usually disables me from getting any work done and really only causes me wasted time fretting over the possibility of not completing work or failing an assignment.
Also, if you're anything like me (and by this I mean if you procrastinate as terribly as I often tend to) then making a list for yourself of practical goals for the day (for example, are you really going to tackle three research papers in one day? Probably not.) can help manage your time better. And this may seem like contradictory advice, but sometimes taking a shower, watching a movie, or taking a nap can help you relax before you begin to tackle an assignment. Sure, it's a form of procrastination, but if you're stressed and can't focus on your assignment, then step away from it for a bit. Drink some tea or color in a coloring book.
If it helps you, write your frustrations out - write your stress out. I often do this in a prayer-journal because who can better handle the weight of my stress than God?
And lastly, as I said before: remember to breathe.