MBA Entrance Exam

50-70 Percentile is general range for OBC and backward classes category of students.

Give as many mock exams as you can and keep rectifying mistakes so that you don't repeat them. Build confidence by being positive for your outcome.

sorry my friend there is not any category system
only marks will be matter approx. 70percent marks atleast you have from 12

You may refer to following link for all details on CAT 2016 examination: https://iimcat.ac.in/per/g01/pub/756/ASM/WebPortal/1/index.html?756@@1@@1

Both have different formats of studying. For CAT, you need to focus on data interpretation, logical reasoning and verbal aptitude with as much as mock exams you can give.
For TOEFL, you need to focus and practice your speaking and hearing skills and need to be well versed with words and synonyms.

Yes, you can apply with December MAT score.

February MAT will not be considered for 2017 admissions.
You can apply via XAT score.

You have cleared the cutoff required. So you are eligible for admissions. New cutoffs will be out shortly.

yes you can. all major b schools in India accept GMAT scores. 650 is a good score. minimum cut off for IIMs is 550 .