So, setting is turning out to be my major malfunction right now. In building a world, I'm finding myself asking a lot of questions I never thought to ask before, things like: What kind of trade goes on? How is the government set up? What is the layout of the land? What is the wildlife like in _____ area? What is the primary mode of travel? Base religion, and how do they worship? The worst part is, some of these may never pop up in my actual story, but I feel like my world should function without my world if I want it to be more real... So, what other questions do I need to ask to have a solid world? What things should I know about this, or at least have hammered down before I throw this setting at my characters?
The setting exists for the story. Only worry about the elements of it that are relevant to the story. Leave the rest undefined. You can expand on it as needed later, but if you nail details down to early, you have restricted your options in the future. Beside, and obsession to flesh out every aspect of the setting from the outset is often just an excuse to procrastinate.
One of the easiest ways to open up the world in your story is describe only the elements that the characters witness, and describe them as they witness them. (random example)
I don't think there's an easy formula for doing this because it depends on your story. Sometimes, if it's a one-off story, and the setting does not play a major role in it, or it's a setting familiar to people (like the present day), just working out the bits that apply directly to your story is enough. If you plan on making a long series based on this world, then I think it's hard to over-plan it. Not planning ahead is just as likely to restrict you as too much planning. If you don't make allowance for some major facet of your world early on and write a story that ignores that facet, you're not going to be able to include it later without invaliding your prior work. But circumventing these sorts of limitations is only one reason to plan ahead. Developing a setting deeply results in all sorts of other benefits: your ideas are likely going to be better thought out and more original, your plots will be more complex and coherent, your environments are likely to be richer, your characters will likely have more depth and interest, etc. It's all about making trade-offs and balancing productivity with originality. Worlds that aren't thought out in great detail tend to be bland, boring, and generic at best and completely nonsensical at worst. Contrary to some schools of thought, it is not better to have ten mediocre novels than one exceptional one unless your goal is just to put food on the table. One of the best ways to actually develop your world is through writing about it. Pick a few significant life events and write about them: write a birthing scene, a marriage, a funeral, a meal, a religious holiday, a transition of power (as when a son assumes control over his father's estate, etc.), a battle, a doctor tending to a wounded solider, etc. Don't worry about names, characterization, plot, style, etc.--these scenes aren't supposed to be included in the final work; just focus on describing the events. Trying to write them out will force you to think about the gaps that exist in your current understanding of your world. (These sorts of occasions help a lot with defining religious observances as well since religion plays an important role in many of them.) This technique is called concepting, which is used in pretty much every other creative medium but seems to be curiously lacking in literary circles. (I guess because authors are supposed to be so smart they don't need to do these sorts of exercises.) The danger in concepting, as Cogito points out, is that it may become a technique you use to avoid writing. That's one of the reasons why it's important to write out the scenes instead of just creating pages and pages of disjointed notes. You should always be writing, even if it doesn't make it into the final cut. Writing is where the magic happens, where creativity and logic shake hands and agree to make something that is both beautiful and coherent. How much you actually need to do depends entirely on your story and your temperament as a writer and I don't think anyone can answer that for you.
Pick out a few essence question to make things relivable. I got two suggestions. "How do people get food, water, building material and clothes in the places the societies comes across?" If you have that questions sorted out, in the whole chain from producer to consumer in broad strokes you have gotten a stable basic for figuring out how the rest the society work if you need it. And as soon as you add some element that will have wide implications it through. "If instant teleportation exists, what sort of things would be possible and how would it effect things? If all men are has to serve a term 10 year in the military and many die during their term how does this effect society at large? " Write down a few essential questions, give them couple of sentence long answer and leave it at that. Let everything else come from conclusions you think fit from thous facts as questions arise from you writing the story. If you try to plan the whole world in advance it more likely that: A: You get stuck at that. B: The things you come up with wont match or make sense in the end because you are trying to paint a to big picture. Chose some essential hard facts for you story, be true to them and shape the world around them as you go.
