Hello, 

These are the subject wise important chapters that would let you score 170+in jee mains

PHYSICS 

Preference 1 chapters

Oscillation and waves,Rotational motion,Electrostatics,Atoms and nuclei,Newtons laws of motion,Current electricity,Magnetic effect of current and magnetism

Preference 2 chapters

Kinematics,Themodynamics,Work power and energy,Optics,Electronic devices,Properties of solids and liquids,EM waves

Preference 3 chapters

Electromagnetic induction,AC,Physics and measurement,Dual nature of matter and radiation,Communication system,Gravitation,KTG

MATHS

Preference 1 chapters

Integrals,3-D geometry,Probability,Conic section,Trignometry,Vector algebra,Straight line,Sets relation and function,Matrices and determinant.

Preference 2 chapters

Limits,Continuity and derivability,Quadratic equation,Permutation combination,Complex no,Circle,Binomial theorem,Sequences and series,Differential eq

Preference 3 chapters

Inverse,Application of derivative,Height and distance,Mathematical induction,Statistics,Mathematical reasoning,Application of integrals.

CHEMISTRY 

Preference 1 chapters

Organic compouns containg nitrogen,Equllibrium,Chemical kinetics,Transition elements,S-block elements,Chemical bonding,Basic principles of organic chemistry,p-block,Coordination compound,Thermodynamics.

Preference 2 chapters

Redox reaction,Biomolecules,Electrochemistry,Atomic structure,Polymer,Solution,Solid state,Some basic concept in chemistry,Periodic table.

Preference 3chapters-

States of matter,Hydrogen,Hydrocarbon,Mettalurgy,Surface chemistry,Chemistry in everyday life,Environmental chemistry,Purification of compounds.

And it depends upon you that which topic difficult or easy for you.

Hope this helps.....