Be self confident first that you will crack the board exams with very good marks.
First try to go through the content that the teacher taught in the class.
If you do not understand a concept, clarify it with any reference book of your choice.
You can also view some videos relating to that topic on you tube.
Prepare the essence of the topic by writing a summary of the topic and the list the formulae used in that topic.
Study some worked examples.
Work out some exercise in the reference book
Study some question bank.
Answer in the quiz section.
Check related questions from previous year papers.
You will be thorough with your preparation.
Do these steps for each and every topic
All the best!!!!!!!