My advice is to not do anything different than what you have done on your practice tests. You should know exactly what you are putting in your body. So make sure to give anything a try before on practice tests before you do it on the real day.
For example, I drank coffee one time before a practice test and the entire test I felt nervous, jittery, couldn't concentrate, etc... I scored poorly. I drink coffee every day at work, but it didn't work for me when I was testing. So I never drank coffee during a test again.
It's my advice that you stay away from a drink like 5 hour energy b/c it really packs a punch and has a lot of "energy" so to speak. You could be wired, and not be able to concentrate. But, if you really want to know, take it during your next practice test and see if it helps you. Some people say that kind of stuff REALLY helps them, but each person is different. Whatever you do, make sure that you do EXACTLY what works best for you on practice tests. If you change things around you could be asking for trouble.