Film genres and openings 
After conducting my research using various online sources, i have found many pieces of information specific to my genre of film here is an extract of a piece of information i have found using slidshare which defines both the general definition of a horror film and their typical audience " Horror• Films designed to frighten, panic and cause alarm for the audience with supernatural characters. Usually for an older audience – 15+ Iconography – a haunted house, symbols of death, binary opposites of good and evil Example films: The Exorcist (1973), Saw (2004) The audience will expect to be frightened with a sense of excitement – ‘what will happen next? the overall definition is described as "is a film genre seeking to elicit a negative emotional reaction from viewers by playing on the audience's primal fears. Horror films often feature scenes that startle the viewer; the macabre and the supernatural are frequent themes. Thus they may overlap with the fantasy, supernatural , and thriller genres.

As far as horror film openings are concerned, I have looked over my previous classwork and I have found the general opening horror film sequence which is as followed:
Film institutions (e.g. Warner Bros) 
( usually two institutions are mentioned in order to evenly spread the cost)
Establishing shots 
sets the tone of the movie
Opening credits/film titles 
shows the films genre,the leading actors and the films writer
Music
This usually sets the tone of the film and may even be accompanied by a voiceover which helps the audience to gain an idea of the plot and build a relationship with the characters which can either be strengthened or weakened during the course of the film

sound
I have chosen to focus more on sound due to the fact that  it  is often a convention that is overlooked due to the fact that it is something that cannot be seen and only heard. Many horror movies such as "the sound of music" ( hyperlinked below) chose to use instruments to dictate the feeling of the audience they may also chose to single out and magnify the sound of a particular instrument just before a key event in order to foreshadow  a significant event and increase the sense of vulnerability within the audience.
https://www.youtube.com/watch?v=-2PsNnj1ftQ