To prepare for JEE exam you can make your time-table. so, that you can complete your syllabus on time and you get proper time for revision. You can set your daily and weekly targets.

To score good marks in your exam it is very important the you have good hold on P/C/M subjects. You should have your basics strong. Take NCERT help to work on your concepts. It is very important to solve all the exercise given in NCERT book you can also go for NCERT exemplar.

Practice makes lot of difference. Try to give extra attention to important topics which carries more weight-age in the exam. You can also solve MCQs.

Solving complete mock test series is very important make sure you do proper analysis. So, that you can improve your performance. It will help you to know where you stand among other competitors. Try to increase your speed as well.

You can check the important topics from the given below link

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

All the Best for your preparation and exam!!