quick shots to hide identity, low key shot or shadow of the character.
Editing: jump cuts and cross cutting are key features which are essential to build suspense and mystery.
Sound: music is essential to understand the mood of characters or a hint at a significant part in the film. It also adds suspense and tension to make the shots more dramatic for the audience.
Mise en scene: the location is important for the film because it helps the audience establish the theme.
lighting is often low key
costumes - antagonist will be in dark clothing. Protagonist will be in ordinary everyday clothes