Dear wamis
The best of learning anything is first understand the concepts and be good at your basics. So for that try to read the text book then try to spend time on reference books. If that is not working then try to attend some video lectures on the topic which you are not able to understand. Try understanding the concept of reactions. Then have each and every chapter weight age so you know which topics have to be concentrated. Then try solving problems from various books and Internet.practice the numerical and try drawing reactions and structures as often as possible. Then you can remember all the things till end. I hope if you have interest in the subject you can easily get through any exams.
All the best.

You just go through the ncert and your tuition notes
This is enough to score 90+ in 12 CBSE
If you want to study more spend time on ncert belong numerical for practice