Kate Messner has a great animated video that talks about her world building process. I transcribed some of her notes so that I could put them into use myself. So here we go. How to go about building a Fantasy World (and how to write a story in that world).
1) Start with a specific place and time. Where is this world? Is it in the past/present/future? Maybe it doesn't matter, but what does matter is that you make a decision, and go forward from there.
2) Create a timeline for your world. What Kate Messner does is creates an outline of the history of her new world. What major events have happened? How did this world come to be? What are the key points of it's history?
3) What rules are in place here? Start with basic things like gravity, light, magic - the rules of physics. Then move into the rules of society.
4) Who is in power in your world? Is there a government, a council, a little psychotic man behind a curtain, a hideous monster demon king? Who is running the show, to what extent, and how, do they rule?
5) What does society value the most? What do they fear the most?
6) What kind of technology exists?
7) Once you have this groundwork laid out, you can start to think about the "regular folks" of your world, and the day-to-day living scenario. What's a normal day like in your world?
For example, what's the weather like? Where do your characters live? Do they go to school or work? What do they eat? Where do they play? How do your characters move around, how do they commute? What do the plants and animals look like?
8) If you spend some time answering all of these questions, you're going to start to get a really idea of what it's like to live in this new world.
But it's not enough just to create a world. Readers and Viewers aren't interested in worlds alone. We're interested in characters. You can have a pretty stage, but you still need emotion and humanity to bring it alive.
Two really good questions to ask, all along, while your world building, are...
*What kinds of characters does this world bring into being?
*What are the central conflicts of this world? Where is the trouble?
Asking these questions will help you come up with the most intruiging scenarios, the ones that will really bring your world to life.
9) In the end, Kate Messner says, drop some characters into your world and let them run wild. See what happens. The key is to get to the point where YOU understand the workings of your world, inside and out. Now you're ready to plop some interesting characters into that equation.
Choose the most fascinating storyline that you can see, from your vantage point as the world creator. And don't start in the beginning - you never start in the beginning - start your story in the middle of the action. Start your story right where things begin to get scary, dangerous, interesting, intruiging, wierd, critical.