hi it means: to ask for the best or the most you could hope for like: You might as well shoot for the moon and ask for a promotion as well as a raise.

Set your goals high - be ambitious.

Shoot for the moon= shoot for the stars= strive for the highest

"Shooting for the Moon" comes from the game of Hearts, where you win every point. Shooting the moon, also known as getting control, capmangoe or running, is a very common scoring variant. If one player takes all the penalty cards on one deal, that player's score remains unchanged while 26 penalty points are added to the scores of each of the other three players. This is known as playing by "old moon" rules. Attempting to shoot the moon is often a risky strategy, as failure to capture even one of the penalty cards will result in the remaining penalty points (as many as 25) being added to one's score.

Set a very high aim that you strive to achieve with possible hardships