Hi arnab2312,
Many Test Takers spend 3 months (or more) of consistent study time before they hit their 'peak' scores, so since you studied for just 2 months, you might naturally improve as you continue to study.
Since we're now entering the latter half of the application cycle, if you are interested in any highly-competitive Schools, you would likely find it beneficial to speak with an Admissions Expert about your overall profile and plans. Those Experts should be able to answer your Admissions questions and help define the specific areas of your profile that could use some improvement. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/As an aside, the 750+ score is approximately the 98th percentile - meaning that clearly most GMATers never score that high. Thankfully, NO Business School requires a score that high. There's no harm in making that your Score Goal, but it's important to realize that the score that you "want" and the score that you "need" to get into your first-choice School are probably not the same thing.
Statistically-speaking, raising a 620 to the point that you can consistently score 750+ will likely require that you commit to at least another 3 months of consistent, guided study - and you'll have to make significant improvements to how you handle BOTH the Quant and Verbal sections. Thankfully, the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level.
1) For your next attempt, are you planning to take the At-home GMAT or are you planning to take your GMAT at a Test Facility?
2) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich