The Q and A game!

Tip 1: Music
Not a full volume though.. without getting to technical your subconscious functions better if you play the music softly. Make sure it's something you can listen to for awhile without wanting to jam out though. It's supposed to be able to just slip into the background. If you focus on the music the whole time, it won't work well.

Tip 2: Water and Exercise
Drink a full glass of water and then stretch before you do your studying. Water is H2O right? Everyone knows this.. but somehow we all forget what that means. It's mostly oxygen!

Water is one of the major sources of oxygen we humans need. You can be low on oxygen without even realizing it. If your low, you feel run down and process things slower. Drinking water and stretching gets oxygen to your blood cells and helps your brain function better, cuz your less tired.

Tip 3: Goals and Break times
It's important to set some goals. Not just a goal of how far you want to get, but how long you'll be studying as well. Don't try to do all that work at once. The brain is a muscle, even if it's full of nerves! If you overwork it, again, your performance suffers.

So remember to set aside time for breaks. I recommend these breaks be at least 20 minutes or so especially if you're studying hard. As far as your goal for what work your getting done, you'll do better work if you break it down into smaller pieces. Since you said your revising something, maybe say "I'll attempt to get X page done in Y amount of time."

Tip 4: Revision Basics
Some times revisions are tough. Your used to seeing something a certain way now, and it can be hard to know where to begin right? What do you remove? What needs added? Is that part really important? It's frustrating! We've all been there.

So sometimes it helps to just take a deep breath and go back to your basics. Why did you write what you did? Is it how you still feel or need? If not, why? Set out two papers/documents. The copy you want to revise and a new, fresh paper you can put your revisions on.

Because I understand what it's like to "not know where to begin" I'm gonna add some links I hope helps you. If for some reason you can't load them (say your country doesn't allow it or something) then let me know and I'll transpose them.

Revision Handout
The writing process
Why Revise This?