The preparation is almost same for AIIMS with that of NEET. The biology is completely NCERT based like NEET.

For Physics and Chemistry you need to do higher conceptual questions of JEE Mains level from books like DC Pandey, Arihant, MTG. You may prefer HC Verma depending on time. Organic Chemistry try having a better and higher concept using notes, for applied questions.

GK Read important year updates.