Hi Aditya!

You have an excellent academic record!!

I am assuming you must be a brilliant student with marks like that. First of all, you need to understand the CAT exam pattern, identify your weak areas and strong areas. While different formats of coaching classes help in preparing for such a competitive examination, a serious self-study plan with online and offline preparation resources is also an option.

The article How to prepare for CAT 2018 will surely help you get started. Now, if you need to find study material and online resources, there is no dearth of help online in the form of videos, mock tests, and other tutorials. Check out the link below for mock tests, sample paper and syllabus.

https://bschool.careers360.com/tags/sample-paper-of-cat

Additionally, some of the good online coaching classes for CAT are provided by HandakaFunda, CareerLauncher, TestFunda, CETking and many more. Just dedicate yourself sincerely in the next four months and I'm sure you'll achieve great success! Goodluck!