I started my prep on 1 Mar with a low score of 530. I completed OG -13 and gave the mock test and got result 590 Q44/V25. It wasn't good indeed. I tried giving 2-3 more tests but I am stuck at 590-600.
Is there anyway out to reach 700 in these 3 weeks remaining...
I think you should dissect your mock tests and focus on the area in which you aren't able to perform as per your expectations.
Q44 is a bit of a bargain..
Try and find out whether it is Problem Solving or Data Sufficiency that needs some polish within Quant and then practice/hone your corresponding skills.
In verbal, again, find out whether it is SC, CR or RC that is asking for more attention and then work on that particular area..
Take up sectional tests every day: 15 ques from SC, CR and RC along with a thorough analysis of each and every question.
The ones that you get right should also be confirmed. You should know why you got them right and make a mental note of the same..
IMO, no one will be able to give you a 'formula' to reach 700 in a limited amount of time.
It all boils down to the amount of hard/smart work you have done and the kind of focus you have..
All the best!