1. “Pick something that could happen to your reader.
2. Pick a location that’s familiar to your reader.
3. Eat, drink, sleep the horror that you have created before you actually begin to write. Lie back in a darkened room and really visualise it. Scare the pants off yourself.
4. Go to your location or one that looks like it and sit there quietly for a while. If your story takes place on a quiet street in the early hours, find one, get up in the early hours and drink it up. Take a pad and write down some notes about what you see and how you feel.
5. Try to see the story from three or four different views even if they won’t be in the final version. Choose someone timid, someone thick skinned, someone religious. The choice is yours.
6. Take your time, build up the pressure, slowly but surely. This may be a short horror story but you’ve got more time than you think to lay out your stall.
7. Stay focussed. Don’t get bogged down in back story. In fact, try giving back story a miss altogether.
8. Anticipation is nine tenths of the horror story battle – let your reader know something bad is going to happen, lead them there by the hand.
9. Dig deep into that horror. Choose one that scares you. If it doesn’t scare you, how do you expect it to scare the hell out of your dear reader?
10. Throw a few red herrings in there, twist them on their heads. The old cat jumping out of the fridge is a bit of cliché but you get my drift.
11. If you’re scared of heights, go and stand on the edge of a tall building and lean over, if you’ve got a spider phobia, go and put one on the palm of your hand. Remind yourself how real fear feels.
12. Don’t overload your reader with gore. It becomes boring and they quickly attain sensitisation. A splash of blood here and there will do fine.
13. Don’t over describe. You’re not Dickens. Give your reader some credit that they can imagine your ultimate horror. Don’t be afraid that they won’t get the point.
14. Keep the monster/horror hidden for as long as possible.
15. Read the best and the worst of horror. Reread the passages that got your heart racing and try to see how the author did it. Look at the way you reacted and imagine that’s what you want your reader to feel.
16. Don’t be afraid to experiment with different styles. Write a couple of different versions of your story to see how it comes out.
17. Leave your first draft for a decent amount of time so that you come back to it fresh. For some people that’s a couple of days. For others it’s a couple of months.
18. Always, always read your draft through once without touching it before you sit down to edit.
19. Check you have the right vocabulary to scare. Choose the words to describe your fear with care. Make sure they fit and sound right. Try not to use unusual words that your reader won’t readily know the meaning to. It will break the flow. You’re trying to build fear not a larger vocab.
20. Don’t forget that your story isn’t written in stone. It can change. It can evolve. It can be totally different from the original. Don’t be afraid to delete stuff that doesn’t belong.“

For more great tips, check out The Feckless Goblin.

[found on http://fecklessgoblin.blogspot.com/2012/02/20-tips-for-writing-perfect-horror.html]