I love horror, but when I tell people I write horror, I can see the wheels turning in their minds. The first thing they see is blood and gore and they think I'm some sort of psycho. It's easy to understand their thoughts, though, as today's modern movies incorporate a lot of unnecessary evils. However, to those of us who live in the horror genre, we know differently. Horror is not about how much blood you can shed. It's about real people eliciting a real emotion from the reader.
When I pick up a horror book, I like to be scared. I like to sit on the edge of my seat, wondering what is going to happen next. Will the monster triumph? Will the main character be able to get out of a sticky situation before they become the next victim? Will I be afraid to go to sleep at night, thinking that something evil might claw its way out from under my bed and take me to a place I'd rather not go?
That is the true face of horror. If I can walk away from a book feeling nervous, scared, or afraid to turn out the lights, then the author has done its job.
I'm a big fan of the less is more concept. The less blood shown spurting from the victim's head as the demon crushes them, the better. Early horror classics never had much blood and gore thrown in. They left that up to the imagination, which is sometimes a lot worse than being shown.
To me, the best horror elements are a sense of evil/dread and evoking fear. Some people can write what they classify as horror by using hospital scenes and people dying. While that may be horror in real life, it doesn't appeal to me. I like to distance myself from real life situations by throwing real life characters into supernatural settings. But remember, the reader must always find a way to get involved with the character or the story will fall flat. If the reader doesn't care about the characters, he/she won't care about the story being told either.
So, how do you define horror?