How do I plan to study for class 12 boards?

Do not worry about the CBSE exams. My advice for you will be –
1. Concentrate on what you study.
2. Practice writing theory material.
3. Practice maths and numericals a lot. Really, A LOT!
4. Keep concepts clear. This is because, when we appeared for exams, there were a few points which were not there anywhere, but our conceptual clarity only made us get them right.
5. Get good sleep. This will enable you to retain more and remember what you have to write in the exam. Also this will help you to be alert for tricky questions.
6. Always take a bath and sit to study before the time your paper starts from today and get up for break when your paper ends. This will get your mind in a habit to be more attentive and in the mood of studies during exam hours.
7. Take sufficient breaks.
8. Have healthy protein rich foods.
9. Don’t forget to enjoy. Go out for a walk in the evening to refresh yourself.

ALL THE BEST!