Hello,

Apart from being well acquainted with JEE Main Syllabus, it's good to know about Important Topics as well mentioned below-

For Physics

Magnetics-One of the topic from which maximum questions are asked in the question paper.

Optics-It is a relatively easy topic to study.

Modern Physics-It is one of the important and scoring topics for both JEE Main and JEE Advanced. Also, candidates must check sub-topics such as radioactive decay of substances, nuclear fission and fusion, dual nature of matter and X-rays in detail.

Electromagnetic Induction and AC- Generally, numerical problems are asked from this topic.

Oscillation and Waves-Must study this topic in detail.

Electrostatics- According to the previous year trend, this is the most scoring topic as almost four questions are asked from it every year in.

Current Electricity- Another important topic which candidates need to cover. Ohm’s law, colour code for resistors etc are asked from this.

For Chemistry

Organic Chemistry- Purification and Characterisation of Organic Compounds, Some Basic Principles of Organic Chemistry, Hydrocarbons, Organic Compounds Containing Oxygen, Organic Compounds Containing Nitrogen, BioMolecules etc.

Physical Chemistry- Some Basic concepts in Chemistry, Atomic Structure, States of Matter, Chemical Bonding and Molecular Structure, Surface Chemistry, Chemical Thermodynamics, Equilibrium, Chemical Kinetics, and Redox Reactions and Electrochemistry.

Inorganic Chemistry- Classification of Elements and Periodicity in Properties, General Principles and Process of Isolation of Metals, Hydrogen, s - Block Elements (Alkali and Alkaline Earth Metals), Co-ordination Compounds, Environmental Chemistry to name few.

For Mathematics

Permutations & Combinations

Definite Integration

Quadratic Equation

Conic Section

Differential Equation

Probability

Determinants

Application of Derivatives

Vector & 3D Geometry

Complex Numbers

Coordinate Geometry; Matrices in Algebra: Circle, Parabola, Hyperbola in Coordinate Geometry

Functions, limits, Continuity & Differentiability

Sequences engineers

Calculus; Definite Integral in Calculus

In addition to important topics for exam, you can also go through JEE Mains question paper with their answer which will be useful in your preparation process-

https://engineering.careers360.com/articles/jee-main-question-paper

You will need to go up-to depth for each topic especially when you are targeting all India entrance exam like JEE MAINS 2020. I'll share you our website link where entire syllabus is described in detail. Check it below. Till then, I'll help you with some guide lines too.. For physical chemistry, solve as much as NUmBER of  numericals you can, try Arihant or GRB PUBLICATUONS. get thorough with your concepts and basics of organic chemistry and byheart like thoroughly remember the inorganic chemistry part.

For physics and maths, you need to be smart enough to tackle the tricky mcqs and that smartness and speed will only develop once you solve large number of mcqs for a topic.. So that skill and agility will develop in you. So I recommend you to get thorough with the portion and start the work staying focused from today itself.

https://engineering.careers360.com/articles/jee-main-syllabus

Bestest of wishes to you. Thank you.