Based on the available profile information we can say that as you are aiming for top schools
then a score above 700 is desirable. However GMAT alone won't determine your chances of
admission; beyond the academics will also help you in determining your candidature and your
work experience plays a vital role as well.

Beyond academics plays an equally important role so make sure you showcase it well. Generally
most of the applicants have a good 4-5 years of work experience. Although it is not just the work experience that counts but also what you did there like-what were your achievements, what initiative you took, what changes you drove in your workplace etc. So to leverage this if you can show that in 4 years you have demonstrated the skills business schools are looking for you could put in a strong set of essays. Hence the quality of your work, your academics and beyond academics will play an important role in determining your candidature.

Start thinking what makes you unique and what's that 'hook' that will be key to your application.

Please tell me how to start and if i am aiming 700. What books do you prefer ?
I am ok in maths but not good in english. Any advises ?

@shareq:

That depends on what score you are aiming for, which should depend on what schools you're aiming at. You should first take a practice test on GMATprep (mba.com) to determine where you stand. Once you've figured out how much you need to raise your score, you'll be in a better position to devise a study strategy.