how to get the best rank in JEE advance 2018 and overcome the weakness of physics ? what extra it requires to get into the iit's?

The only strategy is to get a good rank in the exam you need to make a strict and systematic study plan & I would suggest you to go through well with NCERT books properly as it will help you to clear your basics. To improve your Physics, your prime focus should be to understand the basics of the subject rather than memorizing the formulas. Pay attention to the derivation because complicated questions can be solved using the basics only. There are class 12th topics electrodynamics , optics and modern physics, these are the scoring topics.

Here are some of the preparation tips for the exam you can follow:

Set the targets on daily basis : Your daily study plan must include learning and revision so assign yourself a target for study. This will boost your confidence and avoid time wastage.

Do Practise: Do practise with previous year papers as it will help you also take an idea about the exam & questions so do practise as much you can.

Subject-wise planning: Based on your preference, select subject wise topics to be covered each day. Know your weakness and Refer to the latest JEE Advanced syllabus for your study plan.

Clarity in concepts: Develop a clear thinking process so that when you see a question, you know the correct theory or formula to be used.

Numericals are crucial: practise at least 30-40 numericals minimum on each day of your JEE Advanced preparation. With subjects like Maths, Physics and Chemistry.

Start from basics : Always start from the fundamentals and then gradually move up further as this will help you to tackle even a difficult problem.

Good luck!