Hi Nikitha,
Most Test Takers spend 3 months (or more) of consistent study time before they take the GMAT. During that time, it's common to spend 10-15 hours per week (or more) on the process. So training to face the GMAT is a big task, but it can be broken down into small pieces.
Thankfully, you've now faced the GMAT, so you can use that knowledge/experience to better prepare yourself for your next attempt. To raise your score 250+ points, you'll need to invest a considerable amount of time, money and resources. You'll likely benefit from a GMAT Course of some type (either Instructor-Led or Guided Self-Study), so you should plan to look into the available options.
Most GMAT Companies offer some type of free materials (practice problems, Trial Accounts, videos, etc.) that you can use to 'test out' a product before you buy it. We have a variety of those resources at out site (
www.empowergmat.com). I suggest that you take advantage of all of them then choose the one that best matches your personality, timeline and budget.
If you have any additional question, then just let me know.
GMAT assassins aren't born, they're made,
Rich