“Worldbuilding in some sense is a requirement for all writers. The people and places in fiction may have analogs in real life, but a writer in the U.S. cannot depend on every reader (or even most readers) being familiar with the Lincoln Park area of Chicago or the lower east side of Manhattan, much less the streets of Bombay or London or Ladysmith. The writer therefore has to recreate the real place in her fiction, choosing key details that evoke or imply a raft of other things that add up tothat particular place and culture.
“For those of us who write fantasy and science fiction, worldbuilding is even more of a necessity. The places our stories occur often have no real-life analogs; one cannot travel to Edoras or Cair Paravel to check out the sights and sounds and smells. One cannot look up the fashions of the Galactic Empire or the social customs of the kzinti or Klingons. The writer makes them up.
“One of the first things you find out when you start paying serious attention to this is that every detail you invent implies other things, large and small. A codfish dinner served in a town far inland implies not only a fishing industry, but fast and reliable transportation (or the fish would spoil before they got to the table). The existance of such fast and reliable transportation means news will move as quickly as the fish do, so if you want it to be three weeks before they find out about the magical thunderstorm on the south coast, you suddenly need to come up with a really good reason why they wouldn’t hear about it a day later like everyone else. And so on.”
This link is to Patricia C. Wrede’s famous Fantasy Worldbuilding list. It’s extensive, but by no means exhaustive. However, if you’re new to worldbuilding, this is a great starting point to understanding how your world works. And even if you’ve been building worlds for a while, it’s still a fantastic reference.
there’s this unspoken law in britain that you’re not to phone anyone while doctor who’s on, and it was on and the phone rang and my brother was the one that had to pick it up, and he didn’t even say ‘hello’ or anything, he just picked it up and went, “WHO THE [HECK] IS RINGING WHILE DOCTOR WHO’S ON?” and the person on the other end went, “DOCTOR WHO’S ON? I’LL CALL YOU BACK!”, and hung up.