Everything within the shot will be seen by the viewer, so any equipment or props that don't belong in the scene must be removed.
Clips of film should be cut when the subject is still moving, otherwise it will look unrealistic or staged.
The trailer needs to follow the traditional features of the horror genre. The correct equipment is needed in order to make successful motion pictures that scare and interest our audience.
Low key lighting is more triditional and appropriate for horror films, as everything is exposed when high key lighting is used which takes away the suspense from a scene and the element of surprise.
Non diegetic sound or music needs to create suspense and build tension throughout the trailer and if there's diegetic sound it needs to build suspense as well, but it also needs to surprise and shock the viewer.