A few tips on how to study and get good grades ;D Tested on myself and it works!

#1 Read the chapter you have to study VERY carefully; try to understand every passage, and read it again if you think you didn't get it all; if you can, underline the important passages with a pencil (better if a colored one);
#2 SUMMARIZE! It's an essential step! It helps you remember and makes studying easier and fast, as then you only got to study/revise your summary, not the book/chapter again ;D
#3 Repeat aloud while you study. Hearing your voice 'explaining' the subject to yourself while you study will help you remember things more easily
#4 Don't throw your summaries away after the test!! They can always be helpful in the future, when you got to revise a subject very easily and fast;
#5 IMPORTANT! Take notes of the lesson during the class!!! You'll start memorizing the subject before studying at home, so that you will take half of the time studying and you'll have more time to play or have fun with your friends ;P