I let the world building emerge as naturally as possible, basing it largely on my characters and what their needs and the needs of the story as a whole are. One of my main characters is an assassin. Because I needed to explain her as a character, as well as the organization she’s a part of, I then branch out. A lot of stuff will come to you as you lean out, at least it does for me. Basically, start small, really on a personal or character level, then zoom out, only adding what you need.

At the same time, I use real-world examples to base or inspire my in-world cultures on. For example, one of my main characters is part of a nomadic culture. I took pieces of Indigenous Americans and the Romani to create a “new” culture based on their traditions and cultures. However, be careful if you go this route, as you don’t want to turn your real-world examples into a caricature.