So I retook the GMAT with an original 700 (Q47,V39,IR 5, AWA 5) last week and scored 790(Q51,V50, IR 8, AWA 5.5).
First, I am not a Brainiac but I also didn't put a lot of months of studying so my advise may not be really helpful.
I'm Indian male engineer from Mumbai and I barely managed a first class in chemical engineering with a 63%.
I took the first GMAT in December after 3 weeks of study including 1 week of full time (10 hrs/day) of study before my test. My weakness clearly was being lazy and lack of preparation which made time management a big problem on my GMAT. I remember blindly guessing 4-5 question on verbal due to lack of time and 2-3 questions of quant for the same reason.
My preparation test scores aren't great either (I remember my first prep score being as low as 510 followed by some 630-680 range scores and a few 720-740 scores).
I did soak up the OG (only material purchased for study) fully and practiced a lot of those questions online for my second attempt. I used
MGMAT flash cards and GMAT club for various problems (silent observer of Bunuel's awesome questions and explanations). Probability was my weakness and worked on that a lot too.
For verbal I would highly recommend
Magoosh question and answer explanations (Whatever I could pull up or get my hands on online) apart from the OG.
One thing that worked for me the most is a lot, and I mean a lot of full length practice. (even while practicing from the OG online link i would design practice to match the real timing thing). Another thing I can think of or advise is to take the real test at a time you're most productive (I'm not much of a morning person and my first test was in the morning so decided to take my second test as late in the day as possible). A final piece of advise would be to review all answer explanations of your practice test, including the ones you get correct (so as to know alternate methods / short cuts possible to save time on the test).
That's about it, I guess I'm not the person to write a great debreif (explains my lowish AWA score). So If anyone wants any particular assistance holla up.
PS: If you live in Mumbai, I am willing to give my OG (Beer would be a good way to say thanks if you're a guy and coffee if your a girl, but I am not too demanding

) PM me and I'll get back to you with my Cell #
Cheers

EDIT on 2-10-'15: I've received quite a few PMs asking if there is a secret source or what "Works" for a high verbal, What material should I refer for verbal etc.
I respectfully request everyone to not go down this road. Not that I am not keen to take questions, I would love to be of assistance, but I don't believe you should ask questions like 'What's the Secret' or 'Which book is better'. If you really want to benefit yourselves, take time to identify your weaknesses, understand your most optimum learning style and then make a decision.
I also think there's a lot and lot of great material out there and most of it good. For example,
Magoosh Q&A videos on YouTube really worked well for me, but that's mainly because I like learning through videos. To be precise, here's my take on it: Try out a bit of the free stuff available from every prep company and go for what really works for you. Not what worked for me or anyone. It's important to be selective about it based on YOUR personal learning style.
Of course, the OG is definitely highly recommended as basic material for both Verbal + Quant.
EDIT on 27/03/2015 : Guys I have received a loads of PMs and while I really appreciate all your well wishes and am keen to answer questions and offer any assistance, things are getting crazy busy at work, plus the visa process et al is making life too hectic... Sorry, but I may not be able to respond to most of you soon enough, please bear with me

.... I will do my best to get back to you all ASAP.