Hi biswa1991,
I'd like to know more about your studies and your overall timeline/goals:
1) What is your goal score?
2) How long have you been studying?
3) What materials have you been using?
4) Which CATs have you used?
5) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
6) When are you planning to apply to Business School?
7) Do you know which Schools you plan to apply to?
Thankfully, the GMAT is a predictable, standardized Test, so you CAN train to score at a higher level.
GMAT assassins aren't born, they're made,
Rich