The Greeks originally founded the Star Signs, and this also depends on one's personality, and the date of birth. Some Greeks founded certain star signs, such as Iris and her twin sister Arke founding Gemini, the girl with two faces. This depended on their history, and likely the month that they were born in.
From first to lastEdit
Aquarius: The ocean. There is likely to be many founders for Aquarius. This star sign starts at January.
Pisces: The fishes. There are many founders for this star sign, with Poseidon either founding Aquarius.
Aries: The strong goat. "Ares" sounds like a likely candidate, with him being strong, and the star sign sounds a lot like his name.
Taurus: Likely to be a mild, farm goat. It is likely that farm gods or gods of the shepherd founded this star sign.
Gemini: The girl with two faces. Arke being the bad side, and Iris being the better one. They were both twins, but got separated from each other because of Arke's secret alliance with the Titans.
Cancer: Cancer is either a crustacean, or merely a crab or a lobster.
Leo: Leo is the noble lion.
Virgo: Virgo is the pretty lady holding the flower. Aphrodite coincidentally is a pretty lady, and she is seen holding flowers a lot, so it is likely that she could have founded it, but it would be better to prefer her to be born on Valentine's Day.
Libra: Libra is the weighing scale, and Nemesis would be likely to be seen with one. Since she is also the goddess of balance, she carries a weighing scale around with her.
Scorpio: There are no likely any vicious gods to have founded this, but Hera could have. In her formal paintings, she is normally seen holding a scorpion. Scorpio is the mean scorpion.
Sagittarius: The centaur holding a bow and arrow. Though Artemis and Apollo both are very good at archery, Artemis is always seen holding a bow and arrow everywhere she goes, and she is also the goddess of the hunt.
Capricorn: Capricorn is the mountain goat with gruff horns. No god should have founded this sign, because they should have already founded the earlier goat signs. But again, the shepherd gods could have founded another one.