What do tomatoes have to do with studying?
Our brains need breaks to do good work! The Pomodoro method (named for a tomato timer!) gives your brain - and your spirit - needed breaks so that you can keep working effectively. Time yourself - work hard for 20-25 minutes, and then ... take a (short) break! Eat a cookie! Jog around the house! Watch a cat video! Then get back to work.
After 3 cycles (3 25-minute study sessions and 2 breaks), take a loooooong break. Your brain needs it, and so does your spirit!
Check this guy's use of the Pomodoro to help him with procrastination for school work: