Need help to up my score from 600 to 720

I just finished with my GMAT exam today and got a very shocking 600. (Q 45, V 27, IR 4)

This was a complete contrast to the scores that I got in GMAT Prep 1 (640 - Q 48, V 30, IR 8) and GMAT Prep 2 (680 - Q 49, V 34, IR 7), these exams were given by me a week before today. While giving my exam I realised that my strategy to study for GMAT has failed me more than anything else. I had attended full fledged reputed classes for GMAT in my city and was fairing decently in my mock tests (classes made ones). I was able to improve my Quant considerably from the classes but the Verbal taught there was dependent more on practicing questions in the class rather than constructive theory or a way to attack questions.

This led me into making several mistakes on the final exam as I attacked the questions by reading it unceremoniously without being able to register them. It really broke down my confidence mid way into the exam and I knew I will not be able to score well.

I need guidance to improve my verbal score. Infact I am willing to consider starting my verbal from scratch. My basics need to be polished for I do not have a systematic way in approaching these questions. For my quant I will request suggestions on advanced quant. I do have Manhattan Advanced GMAT Quant. Let me know if that is sufficient.

For starters I have done the following: Will need something apart from the below for my preparation
1) Study material given by the classes
2) All tests from the classes
3) OG 13
4) OG Verbal Review and OG Quant Review - (Only practiced questions, theory was not touched)
5) Manhattan set of 8 (only quant)
6) OG 12

Will wait to hear from you guys

Regards
Ojas