Every men and women is a star, but the star has potential to become a bright one or dying and dead one depending on their spritual fullfillment in life. I am using the astronomical stars in this simile rather than star in other sense. Not sure if they are be relevant, but Astronomy used to be one of my hobbies, and I can relate the Crowley's star and Astronomical stars very well.
As there are billions and billions of stars, there are different people in their sprituality. Crowley wanted us to be brighter star shining above the sky, not the dying ones or dead ones. If one is not spritual or materialist, then he is a dying or dead star forgotten and invisible.
One becomes a brighter star, when one follows the law of Thelema. Do what thou wilt shall be the law.
Again, it is just my understanding, could be wrong. But it makes sense to me at the moment.