GMAT Strategy

My exam is on 20th of this month. I have taken all the Mock test (one each week except between 3 & 4 it was two) of Manhattan(without skipping any section) with scores as below

1)580(Q44,V25) -- this was initial without much prep
2)630(Q45,V32) -- initial few days of prep, thought I was improving
3)600(Q42,V32) -- seeing this postponed my exam by a month
4)630(Q46,V31)
5)600(Q43,V31)
6)600(Q45,V29)

I have been preparing through Manhattan complete series(self study). I was previously preparing from an older Kaplan book till I got Manhattan. I agree that their theoretical explanation is pretty good and when it comes to practice questions I am usually 90% of the time correct but I dont see real improvement in that topic in the test. I am confused regarding that, perhaps I am not reviewing my mistakes properly. When I tried to improve Verbal, through the detailed way the books follow, it came at the cost of time at the end of the Verbal section making me hurry up at the end. I have been reading through the forum and saw people mention error log, which I will create by reviewing all these exams (or a couple of them). I need suggestions or tips with regard to how to improve my verbal and Quant scores. My target is at least 670+ but I am disappointed that I am not even close to that in my mock tests. Even if Manhattan is tough but still the difference wont be more than 30 right ? I will take the GMAT Prep test after 3-4 days. Thanks

Thanks for the advice Rick, I have just taken GMATPrep test with the following scores
670 (Q49, V33, IR 7, AWA word count 579)
The only improvement was that I was following the time schedule mentioned in gmat prep now videos that I found in another topic.

This helped me a lot in keeping up with the time constraint. I was surprised and elated at the score but I know this isn't my real score. I have the confidence that I can aim higher than this. And that I have to stay focused in improving my scores. I had 18 incorrect response in Verbal and 11 in Quant but in IR I managed to get a 7 even after getting 6 (out of 12) incorrect. I will review them now in details and I think If I can improve my Verbal perhaps I can hit close to 700 in GMAT. Any other advices ?

I can aim higher than this. And that I have to stay focused in improving my scores. I had 18 incorrect response in Verbal and 11 in Quant but in IR I managed to get a 7 even after getting 6 (out of 12) incorrect. I will review them now in details and I think If I can improve my Verbal perhaps I can hit close to 700 in GMAT. Any other advices ????