While well-rounded characters are always a boon to any creative work, I feel that settings are often overlooked. My favorite stories have a setting that is a character in itself and smart use of a setting can really elevate the creep factor of any plot.
Isolation is usually a big part of most horror stories because it eliminates the hope of outside help. It explains away why these people don’t pick up the phone and call the cops. Time and time again, we see settings that isolate our protagonists.
In space, no one can hear you scream. The dark, claustrophobic corridors of a spaceship make for a perfect instrument of terror, where help is a few thousand lightyears away. What’s more isolated than a broken city on the bottom of the ocean, where the entirety of the sea threatens to swallow you whole along with its psychotic populace at every twist and turn? How about being stuck with an antagonistic alien organism that can take the shape of all your friends in the Arctic Circle, one of the most hostile landscapes on Earth? What about being trapped for the winter in an aging hotel nestled among mountains known for their snowstorms with a member of your family slowly losing his grip on reality? We see isolating stories over and over again because they work.
By that same token, you can play around with the opposite side of that coin. What if your characters aren’t isolated, but surrounded by people? Body horror and stories about the walking dead have found a way to weaponize cities and other large population centers where the risk of infection increases substantially. Watching zombies pile on top of each other to breach the walls around Jerusalem in World War Z is burned into my memory.
You know what really makes people squirm? The bastardization of their safe spaces. When the places that we go for comfort are upended or even worst, become openly hostile environments, it’s really easy to feel like our lives are spiraling out of control. Perhaps even more pervasive than the isolationist story, horror set in the family home will always be enduring because everyone can relate.
Think about your setting and how it can terrify your audience.