Hi Shiv2016,
First off, if you're restarting your studies after some time 'off', then it will likely take a bit of time just to reacquire the skills that you had before. Beyond that point, raising a 550 to a 700+ will take some considerable effort - and you'll have to make significant improvements to how you handle BOTH the Quant and Verbal sections. That type of work will likely take at least another 3 months of consistent, guided study - so you might need to consider pushing back your planned Test Date.
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information about your prior studies and goals:
Studies:
1) How long did you study?
2) What study materials did you use?
3) How many times have you taken the GMAT?
Goals:
4) When are you planning to apply to Business School?
5) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich