Hi Musicat,
Studying for the GMAT is probably unlike any type of studying that you've done before - to score at a high level, you can't really 'cram' for it. Instead, most Test Takers have to train consistently, often for several months, to hit their goals. In that way, it's similar to learning a musical instrument or training for a marathon. The process takes time.
To that end, you don't have to study every day, but studying in 'small chunks' throughout the week (with larger 'blocks' of study time on the weekends) is quite common.
1) What is your goal score?
2) When are you planning to take the GMAT?
3) When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich