Hi sandeepan688,
First off, a 650/Q48 is a solid Score, so it could be enough to get you into your first-choice School. As such, a retest might not be necessary. Depending on the Schools that you plan to apply to, you would likely find it beneficial to speak with an Admissions Expert about your overall profile. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/GMAC has publicly stated that the Official Score that you earn on Test Day is within +/- 30 points of actual ability. Your 2 Official Scores show that you essentially performed the same each time (about 650 +/- a few points). You handle certain aspects of the GMAT consistently well, but you also leave yourself open to making certain consistent mistakes. It's likely that you have developed some 'bad habits' during your studies that are keeping you from scoring higher on Test Day (which will take time to fix - and replace with new 'good habits' - before you can score significantly higher). As such, focusing on "hard" questions is probably not what you need right now.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long did you study before each of your 2 Official GMATs? How many hours did you typically study each week for your 2nd attempt?
2) What study materials have you used over the course of ALL of your studies?
3) On what dates did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your overall goal score?
5) When are you planning to apply to Business School?
6) What Schools are you planning to apply to?
You might also choose to purchase the Enhanced Score Report. While the ESR doesn’t provide a lot of information, there are usually a few data points that we can use to define what went wrong on Test Day (and what you should work on to score higher). If you purchase the ESR, then I'll be happy to analyze it for you.
GMAT assassins aren't born, they're made,
Rich