Focus on weapons- In many horror films today (excluding psychological horrors) there is focus on the weapons used by the villain of the film. This allows for the villain to have a signature weapon, many films have villains that are notorious for using a certain implement, this may be found by the character during the film or they have it from the start of the film. Jason in Friday The 13th is known for using a machete and there are a collection of low angle shots showing Jason carrying the knife, pointing it at the ground.
Isolation- This is less of a key part in modern horror as it was before but it is still used. Variation in isolation has decreased drastically because most horror films nowadays are set in the woods. In older films isolation was far more creative, for example in Don't Look Now, the isolation is in the fact that they can speak very little Italian. It is used in these films because it highlights the fact that the victim is helpless.
Blood/Gore- This is used to indicate the villains presence and where he/she can go, for example a man comes home to find a bloodstain from a murder, he now knows that it can happen in his home. It may also indicate danger, in some films blood is used to warn the viewer and add tension. Some people are scared by blood and gore so the film has more potential to scare the audience.
Lair- In a large amount of horror films the main villain has a lair, the victims are usually trespassing in it and the villain takes the appropriate measures against them. People in the film always think it is a good idea to investigate the mysterious building or hole in the ground. For example in the Evil Dead (2012) they find a basement that was used for witchcraft, naturally they find a book and decide that it is safe to mess around with the book. This is the catalyst for the whole film.
Night Time- There is at least 1 night time scene in all horror movies, if this isn't the case there will be a scene where the visibility is low, such as fog or rain. This will sometimes be accompanied by a point-of-view shot in which there is sudden movement and scares the viewer. The reason films have scenes where your vision is obscured by something is that you will then fear what you cannot see. It also builds up the tension in the film.