I've secured good %ile in (sslc- 64, hsc-88 and ug-74) Bt in cat preparation I'm weak. Can I get admission in any top b school

One mock test is not indicative of how you will do in your actual CAT exam. If you have good acads then you should think about how you can get a good percentile in CAT and dedicate your efforts towards it. For that you need practice. No one scores a high percentile in the first few mock tests. It keeps increasing as you practice. The more you practice the better you get.

When I started giving mock tests, I did not get high marks in the first few. But after that my scores started increasing. The more mock tests I gave the better I became. Mock tests help you get an idea where you stand but they also help you understand your weak and strong points and how to manage your time. Keep practicing and you will be able to increase your score.
All the best!

See academics and CAT performance both are the essential to get a call from any college for 2nd round of interview. Better the college higher will be the requirements of your aggregate score.

Generally to call students for interview and WSAT  round companies prepare a merit list which is based on the aggregate score of individuals which consists of different parameters like CAT marks, 10th 12th and graduation percentage, work experience, engineer or non engineer, gender with different weightages for different colleges. Generally in the aggregate score 10th 12th and graduation all together has a weightage of 10-25 percentage whereas CAT marks alone has a weightage of 40-50 % in the first merit list.

So as you can see good academic records are necessary to get a CL from top b-schools but you cannot ignore CAT percentile which is the key factor to influence your calls. You are a non-engineer so especially in IIMs you will be getting additional marks in order to promote diversity in their college. And Generally non engineers get a call at a little low percentile than the engineers of same category.

You should work on your basics in order to improve your score and also give lots of mock test along with analysing their solutions which will help you in  overcoming your mistakes and come up with a strategy to attempt your paper which will definitely help you in improving your marks and percentile. It will also help you in knowing your strength and weakness so that you can work on it. Try to prepare well and then go for CAT exam because without that there will be no calls from any b-schools.

All the best for your preparations and exams!!