Best Time to Take the GMAT

Hi,

This year will be the first time that I will be appearing for GMAT.
Can someone please help me out with suggesting the best time when i should take the test. I want to make the most of the preparation time so that I can apply for the better colleges provided I get a good score.

Please suggest me the best time to appear for GMAT and also the last tentative date before which I should take the test provided I wish to apply for the colleges in the first attempt.

Thanks,
Swagatam