As the entire 11-12th syllabus is important but it would be better if you could learn the below provided topics very well.

Physics
EMI, AC, Magnetism, Electrostatics, Ray and Wave etc.

Chemistry

1.Thermodynamics and Equilibrium
2.Electro chemistry
3.Coordination Compounds
4.kinetics,solutions & Bonding
5.Organic Chemistry
6.Biomolecules
also study the compounds of p and d block elements

Biology

1.Genetics and Biotechnology , don't forget to study restriction mapping not in NCERT
2.Neural control , hormonal control , Circulation , Photosynthesis, Respiration
3.Evolution and read ecology from ncert
4.Cell cycle and division
5.Human diseases cure and symptoms


Hope this helps!!!