GMAT Strategy

Hello everyone,
I am fairly new to GMAT. I have gone through much of the stuff mentioned in expert posts and also seen the list of GMAT guide books needed to crack the test. But before i start my practice i would like to know if i have the necessary english and math base to start preparing for this test. To be frank, my communicative english is quite good but when it comes to grammar specific topics, I am not even close to average. Also, since there are a couple of years before I (become eligible and) take the test I would like to know what habits I should adopt which will help me in eventually realizing my goal.
Thanks
P.S. - I am also unaware of the american education system since I am from India. So please advise me on what knowledge should I have at the time I give this test.

I am surprised that your planning for your exam before 3 years. I appreciate it.
Getting into a MBA program in a Top B-school doesn't depend on your GMAT score alone, it depends on your profile as well. I would suggest start your preparation for GMAT, just before 1 year and mean time start building your profile. Read the sample SOP's of students who got selected into top colleges.I would also suggest keep reading Hindu editorial(concentrate on reading speed and diction) it will be useful for your exam. Plan/Save money because B-Schools would require huge amount as fee and expenses.
Lastly, keep reading the forum "I Beat The GMAT" which will has success stories and that will truly inspire you.
This is just my piece and i am no expert for GMAT , I hope it will be useful. All the best !!!