I am interested in that, did you answer it in one of your previous posts?
The first thing to remember is that people are the most interesting thing you have in a setting. You may have a killer magic system, like Ars Magica, but what elevates it is the culture that develops around it. The same goes for Burning Wheel, one of its major strengths is how its creative goals focus on people and their relationships.
So if you want to make a place interesting to adventure in, create a compelling situation involving the people who live there.
Next, you usually have one of two scenarios: either you’re about to start a campaign in a setting you’ve already used, or you’re crafting a brand-new setting for the campaign.
In both cases, I recommend talking to your players individually and as a group. Find out what kind of situations they’re interested in, especially the ones involving people. I say “interview,” but I don’t mean some formal process with appointments and clipboards. It just means you make a point to ask them, before the campaign starts, what kinds of adventures they’re envisioning and what kind of characters they want to play.
You then look for the intersection points between their answers. Unless you’re running a PvP-style campaign where players work against each other, you’ll want to find shared interests and themes they’re all excited about.
From there, if you’re making a new setting, sketch out three or four campaign ideas. If you’re using an existing setting, identify three or four regions or situations within it that would support those interests.
Then you hold a more formal group meeting. Pitch each of the ideas you’re ready to run. Let everyone bounce thoughts around until a consensus is reached.
Now you can begin your preparation, tailored to both individual and group interests, focused on the chosen setting, region, or situation.
With existing settings, you get the best mileage over multiple campaigns by keeping the high-level details broad, but going for depth at the local level. Any part of the setting, no matter how briefly described, can be as rich and diverse as the real world. A city-state you’ve used a dozen times can feel fresh if the players are all city guards, or all come from the same neighborhood, and the campaign focuses on that specific area. If your main region feels too familiar, say it’s heavily feudal, then shift to a different region with a new culture and develop that.
With new settings, you can tailor more precisely to the players' interests since you're starting from a blank slate, but you also have more up-front work if you want any depth at the beginning of play. So, like anything, there are trade-offs.
With an existing setting, the players may need to compromise a bit with what's already been established, but you can often find a way to minimize that. The big upside is that the setting offers more depth and more things to “trash,” as I like to say.
In short, I’m leveraging my players to tell me what they’re interested in, instead of guessing what they might be interested in.
Hope that answers your question, feel free to follow up.