Use the readers senses
I’ve talked about this before, and that is, remember your readers are not solely visual. When you walk into a library, for example, you don’t just see the books, you smell the old paper, the worn leather of the chairs, the wood polish. You hear the hushed tones of the readers, the page turns, the quiet steps echoing through the stacks. You feel the worn covers of the books, the chill in the dry air.
Taste and smell are my personal favourites when it comes to describing settings, they are senses we don’t think of when thinking of locations, but they work extremely well. Many of us suffer smell as a memory trigger, we catch a smell and suddenly we are transported back in time to a memory of a place, event or time. So, using smell will help ground your reader in the setting. Smell and taste are closely related as well, smell being a strong part of taste. Have you ever walked into a carnival or theme park haunted house, they will spray something that makes the place smell of damp and mould, sometimes strongly enough that you’ll taste it on your tongue?
You should keep all the senses in mind when writing a setting. Engage your readers via their senses, touch, sight, smell, taste if possible, and sound. All of these together will help you to build a far more engaging setting something your readers will feel.
Which leads us nicely to my next point.
Make an emotional connection.
When describing parts of the setting use emotive language. The tree was green is effective enough, it does the job in the most basic and literal sense. The tree shimmered emerald in the sunlight immediately invokes a tone, immediately the tree is more vivid in the reader’s eye. The tree’s skeletal branches reached up to scratch the burnt evening sky again invokes a different tone. All these little descriptions are describing the same tree but each one makes your readers feel a different way about the tree, in some, it’s just a tree, in others a thing of beauty, it adds to the feeling of threat.
Consistency
Be consistent with your setting, if you start the story in a frightening an impressive place and then two chapters later you’ve lost interest and your attention to the setting or your language for it has changed then the impact of your setting will drop.
An easy way to keep the setting as a key focus is to have an image in your head of the place. Google searches are great for this, get a real feel for the type of location you’re placing your story and refer to it often. Keep it fresh in your mind.
Subversion
You might also want to consider the horror trope of subversion, taking something people normally see one way and turning it on its head. This is why we see so many scary toys or children in horror films, these things are supposed to bring joy, or be defenceless and adorable, but nope, in horror, they will kill you. Subversion can be used in settings as well, taking somewhere people would usually feel safe and secure and turning it on its head
Letters from a Horror Writer 