Hi student, 

It is seen often seen that board examinations are easier than expected.

All you need to do is pay full attention to the course books like NCERTs for CBSE board. The board examinations always have direct questions from the books in the examination. So all you have to do is to read all the books thoroughly, solve the in between chapter questions and the back exercises. Many a time the questions in the board examinations are a copy paste of the questions given in the books.

So just memorize and read all the chapters carefully and you will easily score 95+. Also, for mathematics practice as much numerical as possible. 

Same strategy applies for class 12th.

Hope it helps.

Good luck.