Hello,

Your basics in Physics, Chemistry & Mathematics should be very clear upto 12th std, you should read NCERT books of Physics, Chemistry & Mathematics of class 11th & 12th at least 2 or 3 times for basics. After that HC Verma for Physics (part -1&2), Biology by Trueman (volume-1&2) and Pradeep Guide on Biology, OP Tendon for Physical & Inorganic Chemistry, and Organic Chemistry of "Arihant Publication" for detail or extra knowledge. 

You should also try to solve the previous years question papers, this helps too much and you should also give the mock test to rectify yourself and build your confidence level.

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All the best.

• Concepts of Physics by H C Verma
• Dinesh chemistry guide
• Pradeep guide on Biology