Hi erick4658,
In general, most people do their best thinking in the first 4-5 hours of the day. For example, if you're trying to decide between studying before going into work or studying after work, then you would almost certainly find studying before work to be more effective (since you should more awake, alert and ready to learn - as opposed to later on in the day when you might be too tired to study effectively). Before I can offer you any additional advice, 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) What is your goal score?
5) When are you planning to take the GMAT?
6) When are you planning to apply to Business School?
7) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich