First, you should not take much stress you should be self motivated and determined to crack your exam.

You should plan your studies. Make proper time table. So, that you can complete your syllabus on time and you get proper time for revision. You should give importance to the topics which carry more weightage in the exam.

Work on your concepts to score good marks in your exam. You can take help of NCERT books

Performing well in the entrance exam depends largely on strategizing the flow and proper time management. You should decide well in advance how much time you are going to give on each subject, based on your strong and weak points. With proper time management, you will surely save yourself from the panic during the actual exam.

Solving previous year papers is the most important and required thing to do if you want to excel in JEE. It will provide you an insight into the type of questions, marking scheme and time duration. Solving these model papers will give you an idea about how the actual entrance exam will be.

Make sure you revise the whole syllabus. You should revise daily to acheive good marks in your exam.

All the best for your preparation and exam!!