Many articles and blogs have been written on Worldbuilding by writers far more experienced than I, such as here and here. Still, some lessons that I have learned may be helpful.
When I began writing my first steampunk novel To Rule the Skies, I had no idea that I was starting in the middle of Professor Nicodemus Boffin’s saga, but at some point I realized that Boffin’s back story would make a fine story in itself. Now that I’m deep into writing another book (the aforementioned prequel), I think a lot about the world I’ve created for my characters to live in (which I call the “Boffin-verse”), and spend a lot of time making sure that it’s all consistent.
To begin, I must say that the Boffin-verse is not too different from the real, historical Victorian Era. So the reader really doesn’t have to make a big leap to understand the world of the book, at least initially. Writers imagining a world more different than ours, one that might include magic, or one with very different social and political conventions, or entirely new civilizations, have a bigger job to do to ease the reader into accepting the environs of the story.
The key, I think, to creating a believable world is consistency. So you decide that your story’s world will be different from the real world by, let’s say, Britain and America never making nice after the American Revolution. In order to make a convincing world from this tweak in history, you must consider the ramifications that will result from it. I think of this quote by the naturalist John Muir:
When we try to pick out anything by itself, we find it hitched to everything else in the universe.
Surely the War of 1812 would be very different. If Canada becomes strategic for Britain to keep the United States in check, how does affect the map of North America? Do the ports in the Atlantic Provinces become as large as Boston/New York/Philadelphia, or do those cities atrophy? Does France, Spain, or Russia become a closer ally to the US? And how does that affect American culture, style, and fashion? If you have your American characters taking tea on Wedgwood china at this point, it’s a bit of a jarring inconsistency that could pop the reader out of his happy state of suspension of disbelief. On the other hand, what a boon for the domestic American porcelain industry!
The writer does not have to come up with all the possible alterations that might occur in a different world, but the changes that are important to the story—that is, to the plot, the characters, and the setting—must make sense. They don’t have to necessarily make logical sense, because the world is not always driven by logic. We’re aiming for plausibility. The invention of personal airships may enable women to more easily travel outside the home. This newfound independence could lead to a desire for better education and career opportunities and later, the campaigns for women’s suffrage and equality. Let your mind wander and you can easily conceive of plausible consequences in the world you’ve built.
I’ve used two tools that enable me to keep track of the Boffin-verse. The first is what I call the Encyclopedia. Others have termed it the bible of their book. It is a list of all the important characters, places, events, etc., in your story with all their important information included. How detailed you want to make it is your choice. I find that adding more, rather than less, information, especially about the main characters, helps me to keep track of them as I write. My Encyclopedia has over 100 entries of various lengths and I’ve been tardy at adding things from my second book.
The second tool I use is a timeline. I keep track of important events in the main characters’ lives and other events that occur in the Boffin-verse. I also keep track of the dates of some events in the “real world”, so I can judge whether it’ll fit into the story as is, or if I need to change the circumstances (an advantage of alternate fiction!). I’ve made my timeline in Microsoft Excel, because I like the ability to shift things around, but it could be written as text as well.
Remember that the Encyclopedia and timeline are tools in service to the story, and not the other way around. I’ve changed details in them many times if it doesn’t fit the story, but only change the story if I’ve erred in remembering a piece of information.
A world built upon consistency and plausibility becomes the stage upon which your characters act. The reader should slip right into it and never question its verisimilitude.