Yes, you can crack IIT in 6 months if you are determined and motivated. Make sure your concepts are clear and you build strong fundamentals. You should give quality time to your preparation don't go for numbers.

You can follow below strategies to crack

1-Aspirants are advised to carefully analyze the paper pattern and the syllabus of JEE. It is important to check the weightage of the topics before beginning with your revision.

2-After the analysis, prepare a time-table of the topics you intend to cover.

3-NCERT books are extremely important. Students must cover the entire syllabus from the NCERTs and then consult other reference books.

4-Physics, Chemistry and Mathematics are equally important and hence aspirants must focus on all three.

5-This is the right time to revisit your revision notes or flash cards so that you don’t miss out the important facts.

6-Solving previous year papers is extremely important. They help in knowing your weak areas so that you can work on them further.

7- Some of the important topics which must be revised thoroughly include:

1. **Chemistry** Alcohol, Phenol, Ether, Redox Reactions, Chemical Bonding, General Organic chemistry, Coordination Compounds, s-block and p-block elements, Aldehyde Ketone, Solutions, Solid State and Chemical Thermodynamics.

2. **Physics** Electrostatics, Heat & Thermodynamics, Wave Optics,Rotational Motion, Wave Motion, Magnetic Effect of Current & Magnetism, Laws of Motion, Ray Optics, Simple Harmonic Motion,.

3. **Mathematics** Circles, Definite Integration, Theory of Equations, Vectors, Complex Numbers, Probability, Three-Dimensional Geometry, Sequences & Series, Matrices & Determinants, Applications of Derivatives.

8-It is extremely important to master the theoretical concepts because only those with clear basics can tackle the all sorts of numerical with ease.

This time is sufficient to get any good  rank in JEE Mains or Advanced. If you seriously going to devote your 6 months , it will be enough. Hours of study does not matter, Matters only,  the time which you are giving to your study it should be with quality. Minimum you can study for 7 to 8 hours in a day with quality.

Know your Syllabus Well: Before starting on the preparation process, there is one important step to be completed. Check on the full syllabus of JEE Main 2018 before laying out your schedule for the upcoming studies.

2. Work on a Time Table: After carefully checking the syllabus of JEE Main work towards creating a perfect timetable which will fit your schedule while leaving enough time to prepare for the examination within the days left. Make sure to add short and sweet breaks in between for some relaxation.

3. Make your Basic Concepts Strong: While it is essential to study the topics mentioned in the official syllabus, it is also advised to study the basic concepts well first. By knowing the basic concepts of the units involved in the examination, you will be able to understand each topics well and in depth. This will result in a greater understanding of the topics and will make it simpler for you to study complicated concepts present in the syllabus.

4. Improve your Weak Points: Stressed over some topics or formulas which you just cannot seem to understand? Give more time and focus on these topics to improve it. Keep small notes and constantly revise those concepts which has been hard to understand. By constantly studying the topics you find difficult.

5. Write Notes and Prepare Flash Cards: Like discussed in the previous strategy, keeping notes greatly helps during the preparation process. Notes written in small diaries are highly accessible and you will be able to study from them anywhere anytime. By writing down those complicated theories and formula and revising them, you will be able to remember and understand them more efficiently. Similarly, create flash cards to help you with quick studies and revision.

6. Attempt Mock Test and Solve Sample Papers: Mock tests will give you an almost real experience of how the examination will be. By solving mock tests, you will be able to work on time management while at the same time understanding the question paper pattern.

Revision: While studying it is important to revise those topics which has already been studied. It is advised that each day, a certain amount of time should be divided for revision purposes. Revision is very important as the syllabus is quite vast and all topics have similar importance level which has to be remembered and known by you.