What sort of engineering are you doing, out of curiosity?
As a general rule of thumb, if you're studying in the sense that you are simply studying solutions to homework, practice tests, and so on, rather than doing practice problems by themselves (meaning, without heavily referring to your notes), you need to rethink the way you study. The aim of studying, especially in advance rather than "the night before" kind of studying, is to get comfortable enough with the material so you actually can "snap" your way through problems on the exam and utilize your time bank as efficiently as possible. Granted, some exams will throw some very tricky problems at you, but at that point you need to realize that those problems have a chance of being there and focus on flying through anything that is trivial in order to better arm yourself with the time needed to tackle more difficult problems.
I'm a little unsure as to why Skyrolla got downvoted, but exercise is a great idea too if you can somehow fit it into your morning schedule or maybe just do some walking for ten minutes. That can help with reducing tension and just making yourself feel good before an exam. I should also add that, realistically, you should focus on your learning and grasp of the material rather than embark on some grand journey to become a better test taker. Some people aren't test takers, though if you are bombing tests hard that's a different story.