See you have an average academic background. So in order to get a call from top IIMs like IIM A, B, and C you need to atoast score above 92 percentile and aim for above 95 percentile in order to convert your call.

For other old IIMs you need to score above 85 percentile in order to get a call and above 90 percentile in order to increase your probability of conversion.

Every college gives a different weightage to every parameters in order to call a student. So sometimes even after scoring a high percentile you are not able to get a call from college. Like IIM B gives a very high weightage to work experience and IIM I gives more weightage to 10th and 12th marks even more than CAT marks.

I am informing you about this part so as you don't get stressed and aim for a high percentile. If you are able to score above 95 percentile then you will definitely get calls from good IIMs, FMS and you will be able to convert it with a decent interview.

As less than 2 months are left for CAT exam so quickly brush up with your basics and give up lots of mock test. Also after every test you make sure that you analyse them which will help you in overcoming your mistakes and improve your marks and percentile.

All the best!!