Hi doclkk,
Indeed, we do see students who increase their score from the 600 - 620 range to 680 -720 range. However, this is generally not achieved without hard work and dedication to studying for the exam. Making that kind of score increase is certainly no easy feat; however, it's not impossible.
In your case, I'd recommend spending more time on the homework each week and be more adamant about diagnosing your weak areas on practice exams. It's important not only that you put good time into studying for the exam, but that the time you put into studying is properly applied to weaker subject areas. (We provide you with assessment features on our CAT Exams that make self-diagnosis simple.)
Also, keep in mind that it might take more than one attempt at the exam to hit your score goal. Sometimes, students will take an exam, not achieve the score they want, and come back for their free Post-Exam Assessment, which is a one-hour diagnostic session with an instructor over the phone. This generally helps students better recognize their weaknesses and provides them with a gameplan for the next time they take the exam, leading to a better score.
Good luck with the class! Be sure to let me know if you have any other questions or concerns.
Best,
Michael Dinerstein
Manager of Online Marketing
Manhattan GMAT
212-721-7400
800-576-4628