1.read out load
2.avoid heavy meal before study
3.take intervals again anf again according to ur interest
4.take power nap in very tired condition.
5.sit upright during study
6.organize ur study according to ur thinking power , when brain is active during any time in day then study hard subjects and when u feel sleepy then study easy and ur strong subjects.
7.keep shuffling ur place of study at time to time to create uniqueness in mind and atmosphere