I had waste my 11th completely but now I am i 12th .Which lesson I sholud study or which type of strategy I should follow to reach Top IIt? Is it possible?

Abhay, We have JEE Mains Knockout package for your preparation. https://learn.careers360.com/engineering/jee-main/.

Alternatively, You need to focus on Algebra, Calculus and Trigonometry. Chapters like Vectors and 3D needs special focus. Complex number is a chapter from which atleast 2-3 questions are asked. So you need to master complex numbers, Vectors, 3D and Definite Integral. You should learn all aspects and results of Algebraic Calculations of properties of conics. Under Calculus, Functions, Application of derivatives need to be learnt too. Trigonometry is a scoring topic and so you need to grasp all the important formulae. Mathematical Reasoning/Determinants/Statistics/Mathematical Induction fetch you quick marks and so you need to cover them as well. Refer to as many as Sample papers as you can.

For Physics and Chemistry follow the syllabus according to the weightage. In Physics, Modern Physics take the top slot with 5 questions. Heat and Thermodynamics, Optics, Current Electricity, Elcetrostatics get 3 questions each. Magnetics has 2 questions and the rest get 1 question each.

In Chemistry, Transition Elements and Coordination Chemistry, Periodic Table and Representative elements take 3 questions slot. Thermodynamics and Gaseous state, Atomic structure, Chemical Bonding, Chemical and Iconic Equilibrium, Solid State and Surface Chemistry and Nuclear Chemistry and Environment get 2 questions slot each and the remaining get 1 question each.

Practise as many sample papers as you can.