When I studied at FIITJEE, these are the topics my teachers told me I have to cover properly for Mains:

• In physics, learn formulas of modern physics, optics, thermodynamics, rotation and SHM.
• In maths, try to learn formulas of coordinate geometry, trignometry and integration.
• In physical chemistry, try to learn concepts and formulas of electrochemistry, thermodynamics, solid, liquid and gaseous states.
• In inorganic chemistry, try to learn block chemistry.
• In organic chemistry, try to learn as many reactions as you can, but first learn biomolecules and polymers.

Hope this will help you to plan accordingly and all the best! 

Below are the important topics for JEE Main-

Mathematics-

Coordinate Geometry
Continuity/ Differentiability, Limits
Complex No., Quadratic equation
Integral Calculus
Sequence and Series
Trigonometry

Physics-

Current Electricity
Electrostatics
Optics
Heat and Thermodynamics
Law of Motion
Waves
Simple Harmonic Motion

Chemistry-

Transition Element and Coordination Chemistry
Periodic Table and Representative Elements
Gaseous State
Atomic structure
Amines
Solution and Colligative Properties
General Organic Chemistry
Carboxylic Acids and Derivatives
Hydrocarbons
Carbohydrate, Amino Acids and Polymer