Sleep and study are closer together than you think.
The rhythm
Begin with your sleep rhythm: go to bed and get up at the same time each day. Do you have exam stress that keeps you awake? Write a to-do list for tomorrow. That helps clear your head.
Listen to your body
Know when you are sharpest and use those moments. Do you feel drowsiness, then go to sleep. Pushing on is counterproductive.
What Harvard discovered
Harvard University studied the link between dreams and memory: dreams train the memory. REM sleep stimulates creativity and problem-solving ability.
The power nap
A 15-minute power nap gives relaxation. 30 minutes of sleep does have a measurable learning effect. Sleep is no loss of study time. It is what makes study time work.