Hi,

Take a look at last two years IIT-JEE papers. See which topic has been given more weightage. Although it does not mean that the same topics will be given weightage next year as well, it should be a good indicator.

Since you have just finished class 12, I would recommend studying the Class 12 topics first.

Physics

Do Electrostatics, Electric current, Magnetics, and Optics first. Then do important Class 11 topics like Kinematics and gravitation. Since you have only one year, take care not to give too much time to any one topics and remain stuck there. Don't try too high level problems. Do problems from HC Verma's book. Try to just learn the concepts fast. If the concepts are thorough, you can solve any problem given sufficient time.

Then do modern physics, units and dimensions. Optics, interference and diffraction and magnetics, electromagnetic induction are very scoring I think. So be very clear with concepts in these topics. Give more importance to these.

Maths

Start with Calculus. Complete calculus first. You will get an advantage here because you will most probably have Calculus in ECE 1st year also. Then do matrices. Then start Cordinate geometry. Then, do 3D Geometry and Vectors thoroughly. These 2 are very easy to learn and master, and they are very scoring.

After that do other topics.

Chemistry

Start with Organic chemistry. Keep studying Inorganic chemistry also side by side. Most of inorganic chemistry has to be learned by-heart so you have to keep revising it again and again. In organic, be very clear with all important reactions and their mechanisms. This is very important.