The word “worldbuilding” brings to mind the process of inventing imaginary worlds. But the notes on purpose and flavours of worldbuilding argue that it extends far beyond invention, and applies to all genres.
The real/imaginary spectrum
In reality, all worldbuilding is a blend of invention and reality. Some genres lean more heavily to one end of the spectrum or the other, but they are never one to the exclusion of the other.
Speculative fiction, particularly high fantasy, space opera, and the supernatural leans heavily on invention. But these worlds always have some roots in the world we know. Readers are human and need at least some familiarity to anchor themselves, otherwise the story itself would make no sense.
In these heavily-invented genres, the story world is nevertheless anchored in something recognizable, sometimes to the extent of becoming a trope. Fantasy is so often set in a medieval society it’s become cliche. Urban fantasy, pretty much by definition, is rooted in a contemporary urban setting, while steampunk (again, largely by definition) has a Victorian foundation. Space opera may include invented worlds and alien species, but those worlds’ foundations are often derived or extrapolated from some known Earthly society.
Other genres strive for reality to a greater or lesser extent – historical fiction and procedurals, for example. But even authors serious about research and aiming for close adherence to facts have to lean on invention. What was it really like to live in first century Constantinople, or Japan in the times of the Samurai? The historical record only goes so far, and is often open to discussion and interpretation. To bring a world to life, the author has to fill in the gaps, sometimes with a bit of artistic license.
Consistency
No matter how real or imaginary your world, one of the big rules of thumb in worldbuilding is to ensure it has inner consistency.
Even in entirely fictitious settings, you’ll be starting from some foundation and building from there. You might be aiming for a close representation, or your foundation might be nothing more than a starting point. The question for you is how true (or otherwise) you aim to be, and by what yardstick? For example, are you sticking to known science, or to known historical facts, or to a real life place and culture? Choose where and how much you plan to depart, and ensure the rules of your world remain consistent to themselves.
Know your audience
Whatever your starting point for your world, consider your intended audience and be mindful of their tolerance for departures.
If you’re marketing your work as historical fiction, your readers will expect period details to be accurate. Readers of hard sci-fi will expect scientific accuracy or at least plausible extrapolation from known science. If you’re writing a realistic procedural or political thriller, your audience will expect accuracy in policies and practices. Contemporary fiction had better paint a convincing picture of the setting, even if it’s an invented location.
More cozy or “softer” genres can be more forgiving. Space opera tends to play fast and loose with science and technology, chosen more for effect with barely a nod to plausibility. Cozy mysteries ignore or make fun of police procedures and general police competence, the very opposite of a procedural. Period dramas use the historical setting as nothing more than a colourful backdrop and accuracy be damned.
Know your characters
As well as inner consistency, your world must pay attention to the human element. This is especially important in an invented world.
Character building is a deep topic in itself, ensuring your characters have credible motivations and reactions as the plot progresses, but what about how the characters as a whole interact with the world itself? Your imaginary setting will place new pressures and constraints or present opportunities to people. How will they respond in a recognizably human way?
For example, you might invent an idyllic world where everyone is altruistic, but can you make it credible? Will peoples actions and reactions ring true to the reader? Human nature says there will always people out to game the system and prey on others’ good nature. So, to make such a world credible, there would need to be some powerful mechanism to negate greed and selfishness.
Human nature is all-pervasive, and this is what makes stories relatable.
Ian S. Bott, Writer and artist 