Hi krishhxa,
To start, you might want to pose your questions in the General Strategy Forum here:
https://www.beatthegmat.com/gmat-strategy-f3.html
Given what you've described, you will likely find it difficult to score 750+ with just one month of studying. Many Test Takers spend 3 months (or more) on their studies before they hit their 'peak' scores. Since you have not started yet, we don't even have a sense of your current abilities, strengths and weaknesses.
Since you're just beginning, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can download 2 for free from
www.mba.com (and they come with some additional practice materials). A FULL CAT takes about 4 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
GMAT assassins aren't born, they're made,
Rich