Hello, 

For preparation of NEET, all you need to do is study from the NCERT books properly. The chemistry subject should also be studied from the NCERT books as they give a proper explanation of each and every reaction mechanism. The reactions from chapters like aldehyde, ketone, halogens, Alcohol and the SN1, SN2, elimination, substitution,  carbonation reactions  are all very important. You need to write it down, make notes and revise it everyday to remember the proper mechanism and therefore, solve MCQs based on the reactions. Along with this make notes about the properties of reactants, products, catalysts, temperature conditions, etc. which are necessary for any chemical reaction to take place.

Hope this helps. Good luck.