Learn how to write horror using strong, pervasive tone
Tone and mood are two elements that contribute to how your story feels. Great tone and mood can have readers' spines tingling before a single character has even spoken or made a terrible decision.
Read widely in your genre
Whatever genre you write in, whether psychological or paranormal horror read as many books by respected authors in your genre as possible. Examples of celebrated horror authors include Stephen King, Edgar Allan Poe, H.P. Lovecraft, Clive Barker, Bram Stoker, Neil Gaiman, Chuck Palahniuk, John Lindqvist and more.
Give wicked characters better, credible motivations
When you write a horror novel, it shouldn't read as though a malevolent force is sitting at a bus stop, waiting to infiltrate your unsuspecting characters' world 'just because'. Give every malevolent character a strong, clear motivation. Revealing exactly what the motivation is can be part of the mystery that sustains your story and keeps readers guessing why unsettling things keep happening.
Use the core elements of tragedy
Horror is best when it's about the tragedy in its truest and most theatrical form: tragedy is born through character flaws, through bad choices, through grave missteps.
Write scary novels by tapping into common human fears
If the point of horror writing (and horror elements in other genres such as paranormal romance) is to arouse fear, shock or disgust, think of the things people are most commonly afraid of.
Terror vs horror: Learn the difference
To learn how to write horror novels, it's useful to understand the difference between horror and terror. Both have their place in horror writing. 'Terror' describes a state of feeling. Oxford Dictionaries simply define it as 'extreme fear'. To 'terrorise', means to use extreme fear to intimidate others. Horror, however, also suggests elements of disgust and surprise or shock. Thus the word 'horror' describes not only extreme fear but also revulsion and a sense of surprise and the unexpected.