Setting is a very important thing to think about before you begin writing your book, mainly because it's the foundation for the story. Setting shapes all the other elements of fiction: plot, character, conflict, and theme. Thus, it's very important to at least begin to ponder your setting before you begin writing.
For most genres of literature, setting will be relatively easy to figure out, especially if the story takes place in our world. However, you should apply basic principles of writer's research to any real setting. I live in a Texan suburb, but unless I'm writing a story that takes place in a Texas suburb, I should probably look up how the setting of the story functions. This is especially important if you're writing historical fiction, since you'll need to know the ins and outs of a certain time period to portray it accurately.
Fantasy and science fiction are a different realm entirely (see what I did there?). You'll have to be very careful to introduce the reader to your story slowly. I find that oftentimes, rookie writers will start their story out with paragraphs of info-dumps on how their world works, sort of like notes to themselves on how the world functions. This can be fairly easily avoided by thinking about how the aspects of their world differ from ours; then you know your world and can introduce it piecemeal to your readers.
I tend to come up with a lot of my worldbuilding while writing, but not all of it. Keeping track of certain things is crucial to avoiding the dreaded info-dump. Worldbuilding is a tedious task, but these starting questions will help any writer (not just fantasy and sci-fi) develop their world a little bit at least. Some of these won't apply to non-fantasy and sci-fi writers, however.
ⶠIs there more than one sentient species? Describe each species.
ⶠWhat planet does the story take place on?
ⶠWhat technological advances has this place made?
ⶠWhat are the common family patterns of your culture? (nuclear, extended, polygamous, monogamous, etc.)
ⶠSocio-economic classes? (rank people in order of status, depending on what is important to the culture [money, job, education, ancestry, etc.])
ⶠHolidays?
ⶠSocial cues?
ⶠPhilosophy of law & commonly known laws?
ⶠReligion(s) and basic beliefs of each one?
ⶠLanguage(s) and writing system(s)?
ⶠDifferent major dialects of these languages?
ⶠStyle and medium of art?
ⶠFamous artistic pieces in the culture?
ⶠLiterary or oral culture?
ⶠWhat are some famous pieces of literature or famous oral tales?
ⶠMusical styles of your culture?
ⶠWhat instruments are used in these cultures?
ⶠStyle of government (anarchy, aristocracy, communism, democracy, feudalism, kleptocracy, meritocracy, military dictatorship, monarchy, oligarchy, plutocracy, republic, socialism, theocracy, totalitarianism, tribalism)?
ⶠWhat effects does this government have on society?
ⶠPolitical parties and current political climate?
ⶠEconomic system:
- Traditional: people produce most of what they need to survive
- Market: buying and selling goods and services
- Command: government controls what/how goods and services are produced and how much they cost
- Mixed economy: individuals make some decisions and the government makes others.
ⶠWhat impact does this economy have on society?
ⶠWhat dishes are common?
ⶠHow is water produced?
ⶠHow is sewage disposed of?
ⶠWhat do you do when you get sick? How good is the medical care?
ⶠCommon diseases in your culture?
ⶠHow do people bathe and take care of themselves? (Hygiene)
ⶠWhat clothing do people usually wear?
ⶠWhat do people live in (houses, boxes, tents, etc)?
ⶠWhat do these houses look like?
ⶠWhat furniture does the average house contain?
ⶠWhat are common goods and services available to purchase?
ⶠWould this culture be first, second, or third-world?
ⶠWhat is the biggest crisis in the society?
ⶠIs there a press? If so, does it have a political slant? What are common views on hot-button issues?
ⶠWhat does the environment look like?
ⶠCommon flora and trees?
ⶠIs there a magic system? Develop it.
- Know the purpose of the magic system: the magic system should serve the story in some way.
- Spell out any plot-impacting rules as soon as possible, and don't break the rules unless there are established exceptions to those rules.
- Know the limitations of various magical powers.
You'll probably get more inspiration for worldbuilding once you start writing the book, but those are some basic ideas and starting points for developing your society and making a good setting. In the next chapter, I'll go over some tips for how to describe things, keeping in mind the mood and tone of what you want to communicate.