How can i increase my score by 100 points (from 600 to 700)

For quant, I would suggest doing ~20 problems at a time from the official guide and then reviewing the ones you got wrong or guessed correctly on. Identify what it is in those problems that threw you off the scent of the correct solution, and make a flashcard with that concept on it. It's also helpful to keep a log of the ones you got incorrectly, so that you can revisit them later and prove to yourself that you've mastered that concept. Even if you've already done a set of questions, it's useful to revisit and drill those problems. I repeated questions many times and when I actually took the test, I was able to relate each quant question to one that I had drilled in the past, and was able to apply the same steps to that problem. Drill those flashcards whenever you have time. Sometimes I would casually leaf through them while sitting on the porch, other times I would have my pen and paper out and would be working through them. Even if you're memorizing the answers to those questions after a while, you're still planting the process of getting to that answer into your brain.

For verbal, I used flash cards as well - but when it comes to RC or CR, I found it most useful to identify the types of answers given, so that I could eliminate them. This is something Manhattan did a good job of explaining; there is also a guide on this site called the Comprehensive Critical Reasoning Guide that covers this. I'll try my best to explain, but basically every wrong answer is wrong for a certain reason. After you've seen enough of these answers, you can categorize them into different buckets and cross them off.

Good luck!