Over the years, I’ve gotten a lot of compliments on the depth of the world I’ve built in the Just Cause Universe series, and more than once have been asked how I bring about that sense of reality to the page. One of the most important aspects, I think, is to remember that your characters do not exist in a vacuum. The world has existed for countless generations before them, and will likely exist for countless generations after (unless, of course, you as the author decide to play your Extinction-Level Event Card). All those prior generations have been filled with people who lived, loved, hated, worked, learned, made mistakes, and died. That legacy is what forms the foundation of your world. It’s not just the accomplishments of the characters or their immediate ancestors; it’s the accomplishments of untold billions. Think about the Star Wars Universe for a minute, and discount everything except the six movies. Although the stories focus specifically on a single family’s adventures and the effect they have upon the galaxy at large, it’s still an entire galaxy. There are worlds that barely get a passing mention. There are countless alien races and humans in the background, coming from a wide variety of lives. Think about the citizens of Mos Eisley on Tattooine, going about their business, conducting deals, running criminal organizations and spaceports. Every one of those people is the hero of his or her or its own story, and those stories can be as fascinating to tell as the one about the Skywalkers. Your world should be like that, populated by real people with real dreams instead of cardboard cutouts.
If you get a hundred people together, you’ll get a hundred different opinions on any given subject. People don’t, and shouldn’t be homogenous in their opinions, ideas, philosophies, etc. One of the places the Star Wars Universe falls down is the homogeneity of the planets. There’s a desert plant, an ice planet, a jungle planet, a forest planet, a water planet, and a city planet. None of those are realistic; pretty much any planet should have some mixture of all of these characteristics. You can have a dominant terrain, but even Tatooine has polar regions that should be much colder, and there wouldn’t have been any settlers at all on a barren planet that didn’t have at least minimal useful resources (like water!). You should put far more effort into developing your world than George Lucas did with his planets. You don’t have to fill your books with backstory and bog down the tales, but you can convey a lot of information just through the interaction your characters have with minor characters, or major characters from elsewhere in the world. Say your fantasy hero goes to buy a sword. What if the swordsmith is from a foreign country? What if she’s a racist? What if her brother is dying from Nothian Crotch Rot and it’s tearing her apart? All those factors will play into how she interacts with your hero, and that in turn fleshes out your world.
I traditionally begin most JCU book chapters with quotations. Many of them are quotes from fictional characters within the JCU that have appeared in well-known publications like Playboy Magazine or on television shows like Larry King Live. These help to give the world a sense of place and time, and subtly remind the reader that the characters don’t just exist in a vacuum.
By putting some attention to detail in your worldbuilding, you create a much more interesting place for your characters to exist, and can give them a lot more to work toward/against.
[this post reprinted with permission from http://www.ianthealy.com/blog/2014/08/the-foundation-of-your-world/]