It's a high fantasy + alternative Earth setting based on a medieval era. Each sign has its own planetary house, godly ruler, distinct appearances, and abilities. Tell me about your sign and what you think your primary role in your house would be.
I'm not quite so sure about this. There are many, many books on astrology that could provide much of the information you're requesting (vague generalities can easily be anthropomorphized, I'm sure). I have some misgivings about it because it sounds like you're asking others to do the work for you, leaving a potential tangle of sharing credit wide open.
Just my .02.
To see what another writer has done with this precise setup, try 'Point of Hopes' and its sequels by Melissa Scott. Completely different world and astrology.
Zodiac by Romina Russell does a good job of this. Remember, sun signs aren't everything!
Forgive me if I'm revealing an interest in an embarrassing and thoroughly reviled topic, but I assume what you're trying to do is brainstorm some ideas based on the twelve signs. Fun idea! BenPaced is right, there are millions and millions of books and websites on the subject of the signs. I particularly like Alan Oken! Also, if you can handle dense and ramble-y, I guess I'd advise anything Jung wrote about astrology, or any of his less out-there pupils. Coming up with sign kingdoms is pretty easy, there are infinite varieties though most would fall into easy cliches.
Like so:
Ares- Mountain dwelling, fractious Proud Warrior Race Guys
Taurus- Dull, prosperous plains-dwellers
Gemini- Educated city-states
Cancer- Sophisticated, water-dwelling matriarchy
Leo- Roman-like empire
Virgo- Mysterious, elf-like kingdom
Libra- Artistic state devoted to neutrality
Scorpio- Aggressive state devoted to war and magic
Sagittarius- Romany-like culture of rogues and artisans
Capricorn- Stern state devoted to law and power
Aquarius- Strange country run by philosophers and crackpots
Pisces- Dreamy, mystical ocean people
And, feel free to do what you want with those, but I would encourage you to read about the signs try to avoid falling into easy archetypes. Signs have some pretty complicated personalities, and their meanings have changed and distorted quite a great bit over the millennia. I think the thing I'd be careful about is not letting it feel like a gimmick, astrology themes have been done before and coded factions can get a little boring if they don't feel realistic and organic. Astrology themed kingdoms should be ancient and mysterious, complex and cryptic, filled with things that seem significant but are actually meaningless, or vice versa! Just my IMHO, it's an entertaining thing to think about.
Also, don't forget there's a 13th sign!
Taurus- Dull, prosperous plains-dwellers
...Can we talk about Taurus? Taurus is probably the most underrated sign, creatively speaking. It gets dismissed as an inspiration on Project Runway, the Taurus guy on Homestuck is the lamest, and the Taurus girl in the film What's your Rashee (Bollywood rom-com) is nuts. I don't buy into the whole astrology thing, but I'm technically a Taurus, and I'm sick to death of Taurus being the pathetic one.
A place to start off for Taurus is of course the cow. Cows are large creatures, capable of injuring people, and yet they also provide a variety of dairy and meat products. This is a contradiction of danger versus provision, of the violent bull versus the tame, content cow chewing on grass. So I guess the Taurus-types must be the risk-takers, the explorers and pioneers, the people who go forward despite apparent danger and have minimal desire for the non-pragmatic clothing. Like, they're going to be the first in line to explore a dangerous cave or create a town in a dangerous wasteland.
Also, I don't imagine they'd have much in the way of government. They'd be the somewhat more disciplined self-government types, more liable to subject themselves to family values than distant monarchs. Probably they'd have sheriffs and governors, and maybe a king who's more like a title-holder than anything else -- the guy whose job is to deal with the governments of the other signs.
Taurus should be all about personal, individual strength, as well as family strength and loyalty. And probably they'd be the ones to find cool artifacts and resources to sell to people who live in safer lands.
I'm a Libra and I would imagine a planetary district based off my sign would be a very opulent one. People living in Libra-Town (I'm sure you've got a much nicer name for it) will spare no expense in making their homes and buildings the most beautiful. Each house would have a green lawn and extravagant gardens, interiors clean and decorated to a T. Arts and culture would be a priority, and citizens of this place would likely see plays, concerts, movies (if this tech is in your novel), and also read a lot, as well as participate in these events. There would be many social events, in which Librans would try to outdo each other with their sense of style.
Families and relationships would likely take on a polyamorous or serial monogamous style of living, although many would be staunch traditional romantics as well and stick to one partner. Either way, the institution of love, in every form, would be widely celebrated. A very strong justice system would also be in place, and many Libra dwellers would be active in whatever social ills plague your planet.
For further info on other signs as well as tinier details, I'd recommend getting a big detailed book of each of the signs and their basic personalities, and then hone in on individual characters using internet info such as "The Signs as X" posts. Such posts are usually found on Tumblr, and basically give out how each sign would react in an endless number of strange and/or improbable situations.
I'd like to put in a word for my people, the Scorpios. We are not 'devoted to war'. We just don't take much crap and if the rest of you don't back off... well, things happen.
Also, probably a monarchy, because that way we don't have regular fights over who's running the kingdom. Okay, there may be scheming, backstabbing and efforts to undermine/ignore the actual king, but at least we know who to point at if things go bad.
I'd like to think of us as being proud mountain folk. Small groups are best, because over a certain population, the bickering, infighting and "You talkin' to me?" gets in the way of getting anything done. Fortunately for the neighbours, this tendency stops us from forming a large army and 'expressing our opinions'. But if we did have an army, it would be the best army! It would be yooge!
If you mean the chinese zodiac, then yes it's based on years. Not all scorpios will be rats.
There's nothing wrong with Rats anyway. All the years are good and bad, both.
I'm not sure how legitimate the 13th sign is, though. Perhaps it can be of interest, however, not really being seen as equal as the others. Hm...
Dude, "legitimate" as in classical. You can't get on Sailor Moon's case just because the Greek gods aren't real, so you can't get on this story because astrology isn't real. It's just for fun. Relax, and just talk about the 13th sign, if you care so much.
Are you more interested in Babylonian astrology (available in a simplified form in a typical newspaper "horoscope") or maybe Chinese or other Asian forms? If you're starting from scratch, it'd be interesting to combine aspects.
I've toyed with the idea of positing that astrology somehow was based on reality, adding FTL technology, and then imagining what interstellar travel would be like in a universe where every star somehow has a magical influence on events and personalities of people living thousands of light years away.
Dude, "legitimate" as in classical. You can't get on Sailor Moon's case just because the Greek gods aren't real, so you can't get on this story because astrology isn't real. It's just for fun. Relax, and just talk about the 13th sign, if you care so much.
Edit: Or I could find a link to a good site.