Use the same text book as your teacher uses. This helps you to revise faster whatever you learn in your school.

But, just be aware that text books are written mainly to teach subjects and not for success in competitions. So, text books are not sufficient for sure success in today's cut-throat competitions in India.

Join some good, reputed classroom coaching.

Generally, there is nothing as good as good classroom coaching. So, you should join a good classroom coaching if you can afford to spend Rs 10,000-80,000.

If not, then you should join some good correspondence coaching (cost Rs 5,000 to Rs 10,000).

Talk to your friends, classmates, and teachers to find out which are the best coaching options in your city.

If you can find, use some special types of notes that allow you to revise a lot of your course material within very short period of time. Such revisions help you to memorize and help get success in competitions