1. Drink black coffee, it helps, trust
2. You need to be interested or stressed to learn, you can cause stress by setting an arbitrary deadline for yourself, if you fail to meet it you have to punish yourself. If you can't do this then have someone else enforce the punishment for you.
3. Make sure you don't forget past material, if you find your knowledge of past material flimsy, go back and UNFLIMSE it
4. Repeat