only method to improve your score is more hard work.
you should give more stress to those topics in which you feel difficulty. or in which you are not much confident.and at the same time you should keep revising other topic also. First you should refer H C VERMA and Resnick & Halliday for the theory part .and see the solved example and then try to solve excersice problem.After that you should see the previous years IIT JEE problem based upon this topic..Try to solve as much problem as you can .
and do not waste your time in solving question that are very difficult .Many peaople frame such a question which are not a part of IIT JEE syllabus.and it is just a wastage of time.
Just stay calm and focus on understanding rather than mugging. Be regular in class and stay with concepts
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