Finals - how do you stay focused?

It's that time of year - Finals are in full swing!

For me, finals meant grueling marathon days of studying, especially when multiple tests were scheduled on the same day.
How do you keep yourself focused during these kinds of days?

Do you study all at once, or break it into sessions?
What helps you get in the zone - music, study groups, flashcards, etc?

Share some tips for other students!