Hi Neha,
It sounds like you're just starting out. Is that true? Have you done any studying so far?
If you're just beginning, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can download 2 for free from
https://www.mba.com (and they come with some additional practice materials). If you want to do a bit of practice first, so that you can familiarize yourself with the general content and question types first, then that's fine - but you shouldn't wait too long to take that initial CAT. A FULL CAT takes about 4 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
I'd like to know a bit more about your timeline and goals:
1) What is your goal score?
2) When are you planning to apply to Business School?
3) What Schools are you planning to apply to?
With an August Test Date, you have plenty of time to study, but you still need to be efficient with that time. Thankfully, the GMAT is a consistent, predictable Exam, so you CAN train to score at a high level.
GMAT assassins aren't born, they're made,
Rich