Practice and clear concept is the key to scoring good.

NCERT and other textbooks like coaching notes form the basic level of knowledge. Now to twist and apply the knowledge gained do MCQ. Physics Exemplar is a good book for clearing concepts but only 50% of chances are there in getting such types of question in NEET and AIIMS.

For competitive exams you must know the approach to the question so as to save as much time as possible. Solving previous year question papers, MCQ books from Arihant,MTQ for NEET, NCEERT at your fingertips are good for NEET.

For AIIMS you need a higher level of conceptual question, so try solving MCQS level of JEE Mains and not Advanced. 

Solve at least 20 mcqs everyday, choke out the exceptional and ones you have done mistake. Repeat them at times. 

Best of luck.