Hi ankujgupta,
A 670 is definitely a good start. Also, once you get your ESR, please share that with us, as it will provide a breakdown of how you scored in Sentence Correction, Critical Reasoning, and Reading Comprehension.
Since you scored a V30 (which is well below those of your practice CATs) on your real GMAT, it may be an indication that you have not fully mastered each verbal topic, or it could be an indication that you were fatigued or nervous on test day. With that said, I have a few questions for you:
1) Describe your study routine. How many hours a day did you study and for how many total months?
Also, when you were studying, do you feel as if you were able to achieve linear and targeted learning followed by focused practice? In other words, were you able to master one topic before you moved to the next? For example, when learning about critical reasoning, were you able to learn about all aspects of critical reasoning: strengthen and weaken the conclusion, resolve the paradox, find the conclusion, must be true, etc. and then follow your learning with focused critical reasoning practice?
2) When you took the practice tests, did you take them under realistic conditions (e.g. in a quiet environment, no extended breaks)? Did you complete the entire CAT, including the IR and Essay sections?
3) Describe your experience on test day. Did you feel nervous while taking the exam? By the end of the verbal section did you feel burned out? Did you take all of your assigned breaks? Feel free to include any other relevant information.
Once we have some more information about your study routine and test day experience, we can provide some more tailored advice.