For doing MBA from institute like IIM you have to have excellent communication skills, thorough knowledge in current affairs and you have to have good aptitude and arithmetic skills. For CAT maths upto +2 is fare enough to score good marks in arithmetic. ut you have to be thorough in that.
Additionally you should have command over English vocabulary.
You can join some coaching centre like TIME for preparing for CAT.
But it is not yet time for that by the end of third year you can enroll for the coaching class.
Read news magazines and competition magazines to update your knowledge in current affairs. eg. Frontline, Competition Success, Competition Refresher etc.
Enhance your vocabulary. Read some good novels.
Polish your school math skills.

Anyways once you join engg you wont get much free time to do all these.

Wish you all the best.

Answered by Rajesh R.K. at 3:57 PM on July 02, 2008