Hi sanya681,
The 750+ score is essentially the 99th percentile - meaning that 99% of Test Takers never score that high (regardless of how long they study or the number of times that they take the GMAT). Unfortunately, no GMAT product can 'guarantee' you a Score at that level. Thankfully, NO Business School requires a score that high - so it's important to realize that the score that you "want" and the score that you "need" are not the same thing.
It's unclear whether you've put in any significant study time yet or not, so it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied?
2) What study materials have you used so far?
3) How have you scored on each of your CATs (including the Quant and Verbal Scaled Scores for each)?
Goals:
4) When are you planning to take the GMAT?
5) When are you planning to apply to Business School?
6) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich