Disclaimer: This is just a low down on what I felt works and what doesn’t. Now, if you search the web for how to study for the test, you will get hit by too much information which can be intimidating. While doing my research, I got acquainted with…
Disclaimer: This is just a low down on what I felt works and what doesn't. Now, if you search the web for how to study for the test, you will get hit by too much information which can be intimidating. While doing my research, I got acquainted with pretty much the best, most extensive tips/material/strategies to take GMAT. Getting a 700+ is doable. I screwed my maths and hence... but nevermind cuz 680 + will take me where I wanna go. 
Before we go further, I suggest you go through the gmat structure at mba.com for an overview of GMAT. It is the official website and you should know the test format like the back of your palm.
What I studied
Basic Maths book - to get my concepts clear. Quantitative aptitude by Arihant. Fabulous Book.
Official guide 12
Official guide 10.
Kaplan Maths Workbook
Kaplan Verbal Workbook
I found this gmat experience particularly inspiring and listened to him regarding what not to study 😃 :http://www.pagalguy.com/discussions/760-my-gmat-experience-25006505
Do you need to take a test series and coaching?
When I had a month to go for gmat, I felt I needed classes and joined a fastrack batch. But somehow I ended up giving only 2 tests at the center and going for 3 classes only! Rest I studied by myself, gave tests in a timed environment at home and took guidance from a faculty at ******** in the last days. If you have time, ******** has a 11 weeks course which is on weekends only. It includes 30 tests and coaching on saturdays and sundays. It costs 30k. It isn't a bad idea at all to go in for this.
If you have discipline and feel (after looking at the gmat material) that you can manage this by studying on your own, you could also study on your own with the material mentioned above and give tests at home in a timed manner. Start at least 6 weeks before you plan to write the test with the first 2 weeks dedicated only to the section you think you are weak at (eng/maths). For english, buy Wren & Martin. For quant, buy the book I mentioned above or another nice quant prep book.
Tests I took
In all, I took 6 tests which constituted of primarily the free tests given at various websites, 800.com tests, and 2 of the GMAT tests that you can download from mba.com. Best part, yeah they are free, give you great analysis, and you can take them sitting at home. In all this will give you around 10 tests which I personally feel are more than enough. What is more important is analyzing these papers.
Free Peterson Test: http://www.petersons.com/testprep/practice_test.asp?id=1727&sponsor;=1&path;=gr.pft.gmat
Free Manhattan GMAT test: Free GMAT Sample Test | ManhattanGMAT
5 GMAT tests from 800.com at 800.com - Toll Free Service - A Revolution in Toll Free Communications!
GMAT Prep Tests : Quality tests, give you the actual feel of the real thing, don't waste them. Use them towards the end of your preparation. :Free GMATPrep Test Preparation Software
DONT'S
-Don't panic over your first mock test score. GMAT is a very learnable paper. Once you get the hang of it, you can build on your score like anything. So don't worry.
-Don't waste time browsing the net for more material or try to get more and more material. Nothing comes out of it and you only end up getting intimidated by it. Zero down on 2-3 books and do them properly
-Don't waste time preparing for essays. In fact spend only 2 days on the essays since they are graded by a machine/human combo and you get a good score damn easily simply by using transitions and building on 2-3 key points. Focus on the main sections.
-Don't compare. If you take the classes-route, it is easy to get disappointed by the know-it-alls in your class. What happens in the class and in the actual paper are very different things, trust me on that.
If I were to go back, what would I do differently?
I'd join the 11 weeks batch in a good coaching institute. I'd learn the key maths concepts under the guidance of a teacher. I tried doing things I had never done before such as coordinate geometry, on my own which didn't quite happen and ate up my time too. 
What I felt worked
I took tests in the last 2 weeks every third to fourth day in a proper timed way and got used to the 3.5 hours structure. If you aren't used to focusing for that long, you will lose out in the actual exam cuz your brain will freeze.
I studied consistently, on a daily basis for three weeks focusing only on studies. This helped me a lot as I had no other work commitments and no other pressure. Just pure, hardcore studies.
Thats bout it for now. If you find that you want to know something else that is not covered here, let me know and I will try my best to give my 2 cents on that.