To write a horror novel, start with characters your readers care about, control the pacing, let the setting do the scaring, and turn the genre's clichés into traps for a twist. Otherwise, writing horror is much like writing any other kind of novel.
If you think about it, reading horror stories is a strange way to spend your time. Why would people enjoy being frightened out of their senses? Whatever the reasons, they keep the horror genre flourishing, and that is good news for first-time horror writers like you.
Writing a horror novel is mostly like writing in any other genre, with a few small differences. Your goal is to scare your readers witless, and the following pointers help you do that.
Explore the characters first
Your readers must care about what happens to your characters. If you start right away with a 10,000-year-old ghoul sucking the life out of your main characters, your readers won't even know how to react.
Let the first few chapters be all about the characters. Setting up a bit of a scary atmosphere at the beginning is fine, but make sure you relate everything to your main characters. How to write a perfect character description helps with this part.
Write about their psychological background, too. It can make your readers wonder whether the paranormal events are real or only in a character's head.
Watch the pacing
You could almost say that a successful horror story is all pacing. An exaggeration? Perhaps, but it shows how important pacing is when you write horror.
Play with sentence length. Give your readers a sense of dread with long, winding sentences. When the horror strikes, use short sentences for more impact.
Pacing is closely related to building tension. Tense moments should be few and far between at the beginning and come closer together near the end of the story. Remember to give your readers some time to breathe and relax before you hit them with the hammer.
Scare with the setting
In a film, a jump scare can make viewers fall off their chairs. You can't do that in a book, can you?
Read The Haunting of Hill House by Shirley Jackson. Notice how she describes Hill House, with its many rooms and hallways, and how she adds the rumors, the noises, and the apparitions. You don't need to see the house with your own eyes to know it is bad news.
Stay away from the obvious
A family moving into an obviously haunted house is a theme that films and horror novels, especially American ones, have used to death. It has become a running joke about how clueless these families are when they go house hunting.
Avoid the clichés unless you have prepared a twist. Use a cliché as a trap that leads your readers to a false conclusion. Once they are hooked, hit them with a twist that defies all their expectations and common sense. It will blow your readers away. For more on how to end a story well, read what makes a good novel ending.