I've been studying since January 1st. I haven't taken a practice exam in nearly 1 month. During the beginning of the year, I've plateaued at around a 610 practice score. I got a 640 on one manhattan exam early March. Last month I took GMAT prep and got q45v34 and hovered around a 640. Difference in the past month has been from working with a tutor. I've spent 90% of my studies ensuring high level of accuracy on all easy/medium questions in both math and verbals.
I am shooting for a 700. If I fall short, no biggy, I'll just take it again one month later.
Strategy for math: From ridiculous amount of practice on all basics, I must not miss anymore than 3 questions out of the first 20. This will atleast get me a >=48 score.
Strategy for Verbal: Miss no more than 1 of the first 10. This should keep me >=40 as long as I maintain my focus throughout the rest of the test.
As for retaking GMAT PREP, I first worred about repeats. Tutor tells me if you are performing at a higher level of accuracy on the first 20 questions than your previous run of GMATprep, you will see an entirely different set of questions later on. Only when your score does not change is when you will see many of the same questions.
What I've learned so far from my tutor who has scored an 800 twice.
If you're at a 600 and want to reach a 700 efficiently, don't spend enormous time studying hard questions on either sections unless you are dead accurate on all easy to medium level questions. High level of accuracy on easy to medium level questions will drive your score to a 720. Above a 720, you will need to do well on difficult questions. Many students at a 600 level will practice with material way beyond their ability. Knowing how to answer (hard) permutation questions does no good if you don't know how to calculate the surface area of a cylinder (Medium). If you screw up on the medium question, you may never see a hard question anyways.