when i had a exam i used to follow a scheme,
i made a timetable of the exams to revise and what time..
When i revise i usually only do for 45 mins.. Then i take a 10 mins break and eat something and i revise again..
Its good to take regular breaks..
And if your mum/dad screams at you for not studying just tell them that you will Explode if you dont rest!
it alsways worked for me..
So:
Revise hard but take regular breaks between revisions..
Make a timetable of what to revise (optional)
Eat Healthy (its a key to keep fit while you study, it might sound stupid what food has got to do revision but being healthy will help you think better.. Junk food will only make studying slower.
hope this helps for the next Exam