Characters

Characters are very important to any story. Horror stories especially need strong characters and plenty of contrast.

Gore: Weak being made weaker allowing the strong evil becoming stronger. Often supernatural and cliched. Much less attention to characters/more to the worldconsequences of actions

Psychological: Strong, memorable character (religious or otherwise respected) being broken down by the evil. Serial killers and power trips. Often normal people; religious

Supernatural Terror: Less intense main protagonist with solely, usually memorable, supernatural evil. Religious or anti-religious. 

Terror: Memorable main character/s with many definable traits that are fed on and manipulated by less obvious evil. Often a broad concept of evil rather than one "character"

There are many sub-genres of horror, however these are the ones that I focus my writing on. When thinking of how to develop the good and bad sides of characters always keep in mind what is going to happen to them, and who is going to be doing it to them. Both sides must be considered. Horror is best pushed when the good guys are shown true evil or are forced to have a falling out. In horror, there does not have to be a happy ending. In fact, I encourage the darker side to win. It presses the buttons of the reader and breaks the formula. When really considering what is horrifying, knowing that the evil is still out there and still at large is a very scary thought. The idea of the good not being good enough is even scarier. This new "formula" pushes the ideas of martyrdom and heroism and shows that they are not always the best choice. In reality, they are the worst choice against such powerful evil.