One way is to play with the senses. Describe the musty smell in the dark room, the feel of the cold air on the lady's skin. Also, create a sense of isolation for the lady. She has no way to escape the room easily. Make the ghost interact with the lady in a menacing way, like it gets closer and closer to her, and she can feel its cold breath on her neck. Another aspect is to leave some things unexplained. Don't give all the details about the ghost, so the reader's imagination can run wild.
Use vivid descriptions. For example, describe the lady's increasing panic as she hears strange sounds in the dark room. Her heart pounding, her breath coming in short gasps. Also, make the ghost's appearance really eerie, like it has a distorted face or glowing eyes.
To make it more terrifying, build up the suspense slowly. Start with the lady just feeling a bit uneasy in the room, then gradually introduce more and more strange occurrences. Have the room seem normal at first, but as time passes, things start to go wrong. Maybe the temperature drops suddenly, and she starts to see things out of the corner of her eye. You can also add in some psychological elements, like the lady doubting her own sanity as she experiences these things.
One way is to make it completely isolated. If it's in the middle of a dark forest or on a desolate moor, it'll be scarier. Also, add lots of cobwebs and broken furniture.
To make 'dark room stories' more engaging, add a sense of mystery. For example, leave clues that the reader has to piece together. If the story is about someone trapped in a dark room, have them find a strange object that might be a key to their escape but they don't know how to use it yet.
For the haunted house theme, make the house seem alive. Have the walls ooze blood or the floorboards creak in a way that seems like they're trying to trap the characters. With the vengeful spirit, give it the ability to possess people and make them do things against their will. For the lost soul theme, make it so the soul is constantly changing forms, never looking the same twice.
First, focus on the description of the dark room. Make it seem really dank and foreboding. Then, give the lady an air of mystery, like she has a sad or angry look. Add some sudden noises, like a creaking door or a howl.
In a 'lady in the dark room ghost story', a common element is the use of light and shadow. The darkness of the room is contrasted with brief flashes of light, perhaps from a passing car outside or a candle that flickers. This plays with the reader's or listener's perception. The lady may also experience objects moving on their own. For instance, a book might fall off the shelf for no apparent reason, adding to the sense of the supernatural.
One common element is the sense of mystery. The lady in the dark room is often an enigma. Another is the use of the dark setting which creates a spooky atmosphere. And usually, there are strange noises or apparitions to add to the fear factor.
One way is to add some spooky sounds in the background. For example, a low, continuous moan or a creaking sound like an old door opening slowly. Another way is to describe the environment in more detail, like a dark and cold room with strange shadows on the wall. Also, making the only child's situation more desperate, such as being lost in a big, empty house with no way out can make it more terrifying.
A bright wall in a dark room can be a focal point for a ghost story. Maybe the brightness is an otherworldly glow, like the entrance to a spirit realm. The contrast between the dark room and the bright wall makes it seem mysterious. A ghost could appear from or disappear into the bright wall. It could be that the wall holds the memories or spirits of the past, and when the room is dark, these things are set free.
To make 'ust scary stories' more terrifying, use vivid descriptions. For example, instead of just saying 'it was a dark room', say 'the room was pitch - black, like a void that seemed to swallow all light, and the air was thick with a musty smell that made it hard to breathe'. Another way is to add unexpected twists. Just when the reader thinks the character is safe, something even more horrifying happens.
Use vivid descriptions. For example, when describing the snarling sound, say it's like 'a thousand demons fighting over a single soul, a guttural, rasping snarl that cuts through the air like a knife'. Also, build suspense. Instead of revealing the source of the snarling right away, let the reader or listener wonder. Make the setting really spooky, like a fog - covered moor or a dark, damp cellar.