Hi swaroop ansp,
A 580 is a solid initial CAT score (the average score on the Official GMAT hovers around 540-550 most years). Raising that score to a 740+ will take some significant work though - and you'll have to make improvements to how you handle BOTH the Quant and Verbal sections. You will likely need at least 3 months of consistent, guided study to get to that level; you would likely find it beneficial to invest in a GMAT Course of some type (either Guided Self-Study or instructor-led). Since it sounds like you have the
MGMAT books, you can start there if you like. I suggest that you study as you see fit for the next 2 weeks, then take a NEW, FULL-LENGTH CAT (with the Essay and IR sections). That score result will help to define how well you're improving and what adjustments might need to be made.
GMAT assassins aren't born, they're made,
Rich