Research into similar products - conventions of a horror movie

There will be various themes throughout my trailer and these are :

Fear - The person/object causing the fear has to be quite scary and this will have to be seen by the facial expressions of the victim.

Realism - The film needs to seem realistic because if it seems completely fake then people wont be scared.

Struggle - The characters will need to struggle or push themselves to the limit in order to survive. No half-hearted attempts to survive because it doesn't appeal to the audience