There are many ways to study and you have to really find out the best way that works for you. One way to stay alert while studying is to have a balanced breakfast, lunch and dinner. Eating properly is one of the keys to success in your way of thinking, absorbing and understanding information. Eating junk food can make you tired and lazy.
Working out at a gym and walking or jogging helps as well. It helps to clear your pores and clear your mind. Working out is good because if you are thinking about the muscle your working, it will be worked and grow stronger. So working out helps to keep your mind actively thinking.
You may also study while exercising. You can throw a ball at the wall and name off a word and think of the definition for that word. Do this for about an hour and see how good your memory is. Say the words and the definitions out loud to make sure you remember them, and you can also do this with a study mate.