Below are the Prioritizing chapters for JEE
Physics
Physics requires you to have a strong hold on concepts. Once the concepts have been mastered, they are very easy to retain. Some chapters for JEE from physics have a heavy weightage in the exams. Heres the priority sequence you can follow chapter-wise.
Mechanics
Any JEE level mechanics problem can be solved by a combination of one or more of these:
    Newtons laws
    Work energy theorem
    Law of conservation of energy
    Law of conservation of momentum (linear/angular)
    Equation of continuity
    Bernoullis theorem

Electricity and magnetism
Thermal physics
Fluids and waves and sound
Potentiometer-related experiments
Optics
Modern physics

Chemistry

Physical chemistry
Mole concept
Atomic structure
Other topics-  Other concepts like Chemical Thermodynamics, Chemical Equilibrium, Chemical Kinetics, Electrochemistry, etc. have nearly equal weightage. So, they can be revised in any order, but remember that a few questions are guaranteed to come from this section.

Organic chemistry
General organic chemistry
Named reactions
Organic synthesis

Inorganic Chemistry

All the chapters are important

Mathematics

Calculus
C0-ordinate geometry
Vectors
Algebra
Trigonometry