The first step is to grasp the basic concepts properly then go ahead to specific applications of the concepts and for that better to complete your NCERTs, solve all the questions, intexts, examples, exercises and NCERTs will be helpful for theory part as well.

Once you are done with this, you can start doing sample papers and previous year papers to know the difficulty level of questions and after that you can go for topic wise mock papers as these will be helpful to know the exam pattern along with this will also teach you the time management skills during exam.

Good Luck!!!