Part of what you have to consider in building your story is, how much room do you have to work with? Physically.
...No, not how many folders and shelves you can commandeer for your story notes, although that is a consideration. But how big an area is your story set in? How big is the skyscraper your characters have to climb, the underground maze they have to wend their way through, the stolen car they have to climb inside and fight off the zombies from? And does the piece of your world you’re working with have enough room for all that?
There are multiple reasons I picked Namhansanseong as a basis for an alternate reality fortress in Colors of Another Sky. Partly the classic realtor’s reason: location, location, location. It’s close enough to Hanyang (Seoul) to get there on a fast horse, and was historically meant as the fallback fortress when Things Went Wrong.
But partly I picked it because, on examination of the info I’ve been able to get so far, it’s big. Over one-and-a-half square miles enclosed by the fortress walls. That gives me a lot of leeway to build what’s effectively a minor fort inside that for the Demon-Callers to use. And they need that fort. It’s not just the barracks; it’s room for martial arts training, housing falcons, an archery range, a place to practice cultivation without killing innocent bystanders... you get the idea.
(Not to mention a place to keep their armory and their library of monster lore. Books take up room. And they need that information. Sometimes they need it very fast.)
It may still be a bit jammed in places and odd things partitioned into corners; the moment an organization has a perfectly planned building is the moment it’s become static, and then starts dying. But I’m working with the idea that since the whole fortress was recently built, the barracks should have a lot of what the Callers really need.
Think about this when you sketch out your story’s palaces, its starships, its seagoing floating cities. What would people use each of these for, based on real life and your story’s demands? What uses were they intended for, and what have people improvised since? Is the massive base inside a volcano enough room for all the fireballs and laser beams to make your characters’ final fight against the villain dramatic? Or have you shoved everyone into the proverbial knife fight in a phone booth? Which can still be dramatic, but tends to get crowded and viscerally nasty when it comes to the actual takedown.
Note, that may be exactly what your story needs. But if not... well. If you want your heroes to do a Dramatic Final Charge with the rising of the sun, make sure you’ve got a hill big enough to charge down!
