If readers want exciting storylines, plot twists, relationships, and characters, they can find them in good books from pretty much any genre. But speculative fiction has something which makes it stand out. Fantasy and science fiction authors have total freedom in creating the imaginary settings of their stories.
These settings aren’t simply used as background or locations where the story happens to take place, they are key elements of world-building, plot, theme, and characters’ journeys. So whether you set your tale in the asteroid belt or a fairy kingdom, push the limits of your imagination. You are the architect of dreams. And unlike a filmmaker, your budget is unlimited. You can go wild. But putting wondrously original settings to the page isn’t as easy as it sounds. Fantasy and science fiction settings must be designed with internal logic and history in mind, combine aspects of the old with the new, and be described in clear, beautiful prose appropriate to your POV character in order to successfully transport the reader into the new world you’ve created.
The Big Picture
In some types of speculative fiction—alternative history, secret history, near future sci-fi, a lot of urban fantasy, etc.—the story takes place in our world, with magic or sci-fi twists thrown in. The article “World Building: Genre Setting Alternate Earth” has some great stuff to say about those. For the sake of this article, however, we’re focusing on designing new settings, such as in a secondary world fantasy (example: JRR Tolkien’s Middle Earth), imagined alien worlds (example: the planet Arrakis from Frank Herbert’s “Dune”), or locations on Earth but which are entirely made up (example: Hogwarts in JK Rowling’s “Harry Potter” series).
When tasked with creating a whole universe, some authors begin by constructing a ‘world bible’ with copious notes about every aspect of the world. Others just start writing and see what happens, then go back and refine the world-building later. Both strategies can work, though the majority of authors are somewhere in the middle. Personally, I recommend planning out at least the basics of your settings, and focusing on those specific aspects that will impact your plot and your characters. In the end, you only actually have to know enough to convince your readers that the world makes sense and extends beyond what is seen on the page.
So, first you’ve got the story’s universe itself.
This might be a purely fantastical realm like CS Lewis’ “Narnia”, or it might be our own universe but set in a technologically super-advanced future like the Galactic Empire in Isaac Asimov’s “Foundation” series. Either way, it may be important to think about the origin and history of the universe and the laws of nature or magic which hold it together. These big picture ideas will influence the details of all your smaller settings.
Settings in Nature
Here we deal with star systems, planets, landmasses, ecosystems, and the flora and fauna of your settings. Depending on the type of story you’re telling, the complexity built into these natural settings varies. In a space opera like “Star Wars”, it's fine to have homogeneous systems: a desert planet, a snow planet, a forest moon, etc. Whereas in Brandon Sanderson’s epic fantasy series “The Stormlight Archive”, the natural settings are designed to be as complex as any on Earth, though uniquely fantastical, with altered gravity, a new evolution of creatures, bizarre weather patterns, etc.
Think about the role the setting plays in your story and how much world-building should be dedicated to the natural locations. You may—or may not—need to plan out things like gravity, geography, geology, atmosphere, weather, sources of water, the origin of life, flora and fauna, evolution, and the food chain.
You can read more on some of these aspects in the article “World-Building: Geography, Geo-Politics, Maps”.
Settings in Civilization
Now we get to those settings which were constructed by humans or nonhumans, your kingdoms, cities, castles, towns, taverns, ships, spaceships, laundry rooms, the cozy cockpit of a starfighter, etc. The amount of work that goes into designing these settings depends on the breadth of your world, how similar it is to Earth history or Earth science, and how your characters will interact with the space. This is also where your world-building of culture comes into play big time. For example, if your story takes place in an imaginary metropolis, you may need to consider things like natural resources, infrastructure, technology, architecture, transportation, and food production.
Other times, these aspects are less important. JK Rowling never actually writes a sweeping description of the exterior of Hogwarts castle, simply calling it a “vast castle with many turrets and towers”. She knows that most readers already have a general idea of what a European castle looks like and will fill in the details using their imagination. This technique is helpful later on when the plots required new details about the setting (the astronomy tower, the greenhouses, the owlery, etc). By keeping the initial depiction vague, she didn’t have to worry about working within the constraints of a previous description. But if instead of a castle, it was Hogwarts Kravitorium (a word I just made up), Rowling probably would have described more detail from the start.
How Much Makes it to the Page
Occasionally an author will work so hard designing their worlds that they feel all those details need to go into their book. This is called world-builder’s disease and can be fatal to your story. Most modern readers don’t want massive info dumps. They want to learn about the setting as the characters experience the story.
It is true that by default, most fantasy and science fiction settings will require more description than in a mainstream, contemporary novel. If you reference the New York City skyline, readers can automatically picture it in their heads. But if you mention the ‘Quazarathos Magepillars’ or a ‘Xenoreef Starscaper’, no one will know what you mean unless you spend additional words to describe them. An author might want to leave everything up to the reader's imagination, but typically fantasy and science fiction readers want more.
When it comes to what to include, pick those aspects which you are passionate about and which relate specifically to your story. Let’s say you’re writing a science fiction novel about a colonist family setting up a farm on an alien world, only to have an alien bug migration routinely destroy their crops. In a classic man vs. nature story like that, you probably don’t need to know much about the geological history of the planet or the evolution of the alien bugs, unless those details come up in the plot. But you’ll definitely need to have a handle on the planet’s atmosphere, weather, soil, flora and fauna, and food chain, as well as the colonists’ technology and agriculture.
Viewpoint as World-Building
Unless you’re writing in omniscient third person, the reader shouldn’t be given a video camera view of your world, but instead experience it through the eyes of your POV characters. So in revealing the setting, consider how those characters see the world. Have they grown up here and therefore take it for granted? Are they experiencing it for the first time with a sense of awe? Or a sense of fear? A good way to do this, and also avoid info dumps, is to design your POV characters based on the sort of setting detail they would naturally notice. For example, a scientist, architect, or surveyor is going to point out certain features in the setting. Or you could make the POV character passionately curious about the world.
Follow the Logic
The prewriting stage is a good point to look out for potential holes in your plot and world-building. An author can’t stop when they come up with a clever idea, they have to think through its implications. So if you say your story is set on a planet twice as big as Earth, how would that additional gravity affect the landscapes, the evolution of the aliens, or the physical dynamics of your character actions? If you set it in a village of sorcerers, how would their magical powers have changed the way the buildings were designed and built, or how they get their food and water?
It’s easy to get lost in the nitty-gritty aspects of world-building fantasy and science fiction settings. We want to make sure every detail is vivid and accurate and that readers can’t find any holes in our worlds. But don’t bury yourself in worry. First and foremost, have fun. You’re not writing an academic paper to be scored by some professor with a checklist of dos and don’ts. You’re transporting readers to somewhere they’ve never been before. You are an artist, an entertainer, a tour guide of the strange and fantastic. Go blow some minds.