Focused Analysis

Horror films are typically dark with selected lighting used, the darkness represents the unknown where danger lurks striking fear into the hearts of the characters and the audience. Tension can be created with the use of streams of light from the distance gradually making its way toward the screen. Quick flashes of light are used, innocence can be portrayed by softly lighting a characters face. 

What a character is wearing can help identify which genre you are watching. For example if most of the characters were male and in army gear, you would say you were watching an army/war film. In horror films the main costume design doesn't vary much from say a comedy, however throughout the film the costumes may become torn, covered in blood or dirt trying to escape from a murderer, identifying the film as a horror. On the other hand the murderer can be dressed in obvious attire related to horror such as dark clothing, a mask/large hood or cap to hide their identity.

Props can give a genre away relatively easily however you have to be careful not to break the verisimilitude by having an object that doesn't fit with the genre. Props in horror films are typically weapons such as knives and guns, used by the perpetrator but also used as protection by the characters.
The position of objects and characters in a frame can portray different meanings, for instance if you had a character peering round a door in the distance in the left hand corner and the rest of the frame is of the room they are peering into connotes the meaning of anxiousness hoping the room is safe to enter. However if we had that same character standing in the middle of the room their legs shoulder width apart and arms on their hips suggests they are comfortable in their surroundings.

Horror films are typically set in an isolated area with little escape routes such as roads. For example 'The Shining' was set in a large hotel (which makes the characters feel inadequete in comparison) in the middle of no where, we know this via the opening sequence of a long car journey with far long shots and establishing shots. Any location connotes the sense of helplessness, which engross the audience. Many locations even some in towns or cities they have a sense of abandoness to them such as 'Silent Hill'. Other settings horror movies are sometimes filmed at are woodland areas the trees obstructing the path during chase scene adds suspense.