Hey Maxmanish,
You are not alone. The question you are asking has been asked dozens of times here on the forums. So, as a beginning to the hard work you have in front of you, I would encourage you to search through the forum for answers to this question. It'll get you acquainted with the various ideas that have been floated. Remember, there's no simple answer to improving your ability on an entire section. You need to be a good reader/writer in English (so if that's an issue, you could consider taking more basic English classes, and making sure you read books/magazines in English regularly), and you need to be good at the specific things tested by the GMAT (for which there are many books and classes available).
Good luck!
-t
Tommy Wallach, Company Expert
ManhattanGMAT
If you found this posting mega-helpful, feel free to thank and/or follow me!