How does a bad GF act? How does a good GF act? (Preferably Boys)

I'm not a boy, obviously.
But a good girlfriend will support her man, help him to achieve his dreams, while keeping hers in mind, and standing her ground when need be.

In other words, just love him and take care of him. and try not to be a gold digger or an unnecesary bitch. (However, don't be a push over either, think of yourself too, not just him.)