The Greeks would create temples to worship their gods and goddesses. For example the temple of Athena is on the acropolis and I have actually been there. :) Medusa however was not a follower of Athena though did live in Athens, the city named after Athena. In many variations of the tell a basis is formed around the fact that medusa was once a beautiful maiden who angered the goddess Athena, claiming she was jealous of her beauty. Athena then turns Medusa into a gorgon, becoming one of the three monstrous gorgon sisters. As far as worshipping goes they would give offerings to the gods on an altar, food, gifts, sometimes even the burning of animals.
Hope this helped!