First of all, Ravnica is civilized. There is law and order, there is intrigue, there are webs of relationships and (grudging) compromises. It is extremely hard to live self-sufficiently and without interference from others. People who survive on Ravnica most often do so by aligning themselves with a guild or philosophy and cleaving to it or by selling their loyalty and swimming the dangerous seas of the guild-less. But Ravnica is still a fantasy world, so its civilized nature poses some interesting questions: in a world of stone towers, what does a dryad look like? Wouldn’t a minotaur be an awesome architect, given that you kept it fed? Is it right to feed people to a minotaur just so it will design you the best garrison ever?
Second, Ravnica is spiritual. This doesn’t mean that everyone is Deepak Chopra, it means that Ravnicans have very specific beliefs that they hold deeply. Conflict very often arises from differences in opinion in which neither side will back down. A good example of this is the case of the spirits that haunt Ravnica. All over the city there are mostly indistinct or bizarre ectoplasmic creatures that flit in and out of this reality. Everyone calls them spirits because of their confusing and emotionally elemental behavior. Some people call them the souls of the dead. It’s very unclear whether they are or not but everyone has an opinion that they are convinced is right. Conviction, whether constructive or destructive, is morally right on Ravnica. Knowing what is best and acting on it is a higher calling.
Knowledge on Ravnica, both technological and spiritual, is sequestered. The factions you guys will be creating and representing are called guilds for a reason: they control their information fiercely. Knowledge is power and prestige and everyone, whether in a guild or not, husbands their secret techniques very, very carefully. Whether this secret is a blueprint for a printing press or a material ingredient for a fireball spell it is guarded with the most powerful and deadly protections. Of course, this making spying the most lucrative and most deadly profession in the city.
Magic on Ravnica is very specific and widespread. This is a fantastical world where the local merchant might be a dragon or at least related to one. Fantasy species of plant and animal abound. Wild magical events may be common occurences. But magical spells, that is magic that is controllable, is basically a kind of technology. It can be taught to anyone but each type of magic is a specific field. Think of the sciences: Geology is very different from biology; likewise, geo-empathy is very different from anatomancy. Guilds specialize in one or a few of these specific fields and leverage them to spread their influence over the city. This is why their secrets are so closely guarded. Their magic and technology secrets are their source of power.
Lastly, Ravnica is rebuilding. Just recently a 30 year war ended, but not after touching almost every corner of the city. It was destructive and terrible but it ended in the Guildpact, a magical truce between the ten most powerful guilds on Ravnica that promised peace for 1,000 years. This, of course, was the least satisfying compromise for everyone. But now everyone is trying to put the pieces back together (or just looking like that’s what they’re doing). As we know, though, some swords are sharper in peace…
And as an important side note, the culture of Ravnica is based on Late Medieval/Early Renaissance Eastern Europe. So when making up names, I recommend looking up any Balkan names and especially the more outlandish Romanian names. I’m assuming that roughly one language is spoken widely across all of Ravnica and it is a weird Tolkien/Latin pidgeon language as spoken by Count Dracula.