CAT Preparation

You can go for self preparation. Along with that, you must join a good test series. Regular tests will help you evaluate your performance and work on the weaker topics. Just keep working hard and be determined. Keep notes of important formulas and short cuts.

Some of good coaching institutes in Bangalore are -
CET Tutorials, Career Launcher, Career Plan, IMS Learning centre
In Chennai-
Brilliant Tutorials, Magnus Institute, Ascent Education, Career Launcher. In Trivandrum-
TIME, IMS, Greens Educational Consultants Pvt. Ltd., Career Launcher.

For Quant
Arun Sharma How to prepare for Quantitative Ability for CAT published by Tata McGraw Hill
Arun Sharma The Complete CAT Digest, by Tata McGraw-Hill
For Verbal
How to Prepare for the Verbal Ability and Reading Comprehension for the CAT by Arun Sharma and Meenakshi Upadhyay
Nishit Sinha The Pearson Guide to Verbal Ability and Logical Reasoning
For Data Reasoning
How to Prepare for Data Interpretation & Logical Reasoning for CAT (Tata McGraw-Hill) by Arun Sharma.

Refer college rankings of reputed magazines. I got into Doon Business School, Dehradun last year with 93.5 % in CAT.

Hello Vishnu,
Good to see your interest in CAT for preparation. You can refer some past year question papers booklet, also keep yourself updated with current affairs, work more on English, reasoning and aptitude and for better preparation you can join any coaching classes. Good luck for your presentation ahead.

CAT analyses the skills of the aspirant in four sections: Quantitative Aptitude, Verbal Ability, Logical & Analytical Reasoning and Data Interpretation. It is also a test of time management. A detailed CAT syllabus is mentioned at the link provided below:
https://www.shiksha.com/mba/exams/cat/syllabus
Regards.

You have to give at least one entrance exam. It doesn't need to be CAT only. Even MAT and several other such exams can get you through.

Considering the fact that you have low scores, it wouldn't be easy for you to get selected in IIT, even with your reservation. But, if you really want to continue your studies outside India you can.

Eligibility for MBA programme: The prospective applicant must satisfy one of the following eligibility criteria for admissions to the MBA programme. A graduate degree under 10+2+3 or 10+2+4 pattern under any discipline, securing at least 50% marks in aggregate, from a recognised university. Top MBA colleges are as, Indian Institute of Management Ahmedabad, CAT GMAT Indian Institute of Management Bangalore, CAT GMAT Indian Institute of Management Calcutta, GMAT CAT XLRI Xavier School of Management, Jamshedpur, etc.

I am suggesting you five apps for CAT preparation and this might help you for the entrance exams.
1) Aptitude & Logical Reasoning Android app for CAT exam
2) Verbal Ability and Reading Comprehension Android app for CAT exam
3) CAT / XAT MBA Entrance Exam Preparation Android app for CAT exam
4) CAT MBA Exam preparation Android app for CAT exam
5) Vocabulary builder Android app for CAT exam
Please refer these apps to have an idea the various question patterns available for entrance exam in the coming future. All the very best.