GMAT

Aditya, in India, the GMAT exam is accepted for admissions at more than 200 programs offered at over 100 business schools.
Some of these B-schools are the ones that actually started the trend of MBA in India and made it a degree to with. Some of them are new ones in field of imparting management education. But they also have made a name for themselves with accreditation from reputed associations like ACBSP and by offering good placements to students.

First of all you should be clear with the exam format of GMAT .The GMAT exam consists of four sections:
Analytical Writing Assessment (AWA) Essay
Integrated Reasoning (IR) Section
Quantitative Section
Verbal Section
Below are some key points which you should keep in mind while preparing for GMAT:
1.Be consistent and follow your routine.
2.Focus on your weaknesses.
For more tips ,click on the link- https://edudrona.com/questions/question/gmat

Get more information about GMAT and GRE https://edudrona.com/gmat-vs-gre/?mref=oshipau

Hi Jayesh,
You can find a list of coaching centers here-
https://testprep.shiksha.com/ielts-exams-coaching-classes-in-ahmedabad-categorypage-14-51-930-0-0-30-109-2-0-none-1-0
https://testprep.shiksha.com/gmat-exams-coaching-classes-in-ahmedabad-categorypage-14-51-928-0-0-30-109-2-0-none-1-0#cateSearchBlock
Hope it helped.

For executive program there is a minimum work experience cutoff of 5 years. Once you complete 5 years you can apply for executive program at IIMs.

GMAT scores are valid for five years only.

Dear Vipul,
3rd year of b.com is best time for appearing for GMAT reason being if you appear at early stage and manage to score good but still you won't be getting admission till you complete graduation and by the time score validity will be expired.so it is advisable to appear for in final year after exams.
All the very best

Hi Vipul,
Though you must device your own strategy you may read this
http://www.mba.com/global/the-gmat-exam/prepare-for-the-gmat-exam/test-prep-materials/the-gmat-prep-timeline.aspx
Hope it helps. Good Luck.

above 250 score is to possible it