CAT

Hello,
No CAT scores is valid for one year as you need to give the exam again.
All the best.

Hi Vikash,
Until last year you'd have to score 98.5 percentile for interview call and over 99.5+ percentile to have a realistic chance of converting the interview call into an admission offer.
With the admission criteria changing this year, some changes are expected to take place.

CAT is a test of how active, hardworking and techniques knowing you are.
To learn techniques you may join a coaching institute and try solving every type of questions. Don't go into detail, try variety of questions. Keep watch on the pattern of the exam.
Do mock papers and keep working.

I will keep this answer as short and accurate as possible.
It depends on how you define decent college but 90+ overall and in both sections should suffice.

You have scored well in graduation but your high school and intermediate scores are much less for IIMs, especially in case of top 6 IIMs this will act as your negative point so you need to get above 80 percentile in CAT according to me.

CAT exams usually take place in the month of December. This year it will be held anytime in December 2018.

Above 85 in CMAT and MAT will fetch you good colleges.

Try giving another attempt and give the MAH-CET exam, aim higher this time as it's very much easier than CAT, as well as it is easy to crack. Doing so, you can aim to higher and better colleges in the city.
With 65.86 you would get average institutes.

Hi,
As you are going to appear for CET, try giving various mocks and focus on your strengths. Try aiming at 90s, as it would get you a good college with good placements.