Primary character is talking to spooky character. Primary looks away, looks back, spook is gone.
Primary character is preparing for bed/bath/whatever. Primary looks away, looks back, spook is suddenly there.
Person who is talking on phone suddenly notices something, stares at it, and slowly puts the phone receiver down, so all that is heard is the caller saying “Missy? Are you there?.. Missy, what’s happening?”
Primary character sees the villain out of the corner of her eye, looks away, then looks back and there’s no one there.
I like the way they did this in Scary Movie, except they kept the camera on the villain, and you see him run away when the primary character does look away for a second.
The cheapest possible way to make your audience jump:
Character goes into area where danger is known to exist. Sound track is turned way down, music very quiet and in a minor key.
Something jumps out. Soundtrack plays jarring chord at full volume.
with the lights out, the intruder is more familiar with your house than you are.
The main character is hanging by his fingertips on the edge of a cliff or above some other huge drop. Will he fall to his death or somehow make it back to solid ground? Oh, the suspense!
“It was a dark and stormy night, I had just taken a creative writing course” -Crow T Robot, MST3K
The hero has overpowered the killer, has him tied up, and is holding a gun on him. He starts to back out of the room…
and bumps into the REAL killer.
We are nearing the end of the story, when the identity of the Mystery Person will finally be revealed. So, until then, let’s just aim the camera at his feet and follow his every step until we’re good and ready for the big finish. Feet walk along passage way, go up stairs with a menacingly relaxed pace, turn, go along corridor, go through door… blah blah blah… until the director has finally had enough and actually pans up to give us beauty shot of the villain’s face.
Villain and main character battle, one of them had a gun but it was knocked free and lays on the ground. Villain and main character wrestle on the ground, both struggling to reach the gun, almost touching it. Finally one of them grabs the gun, the gun goes off, both of them wince in pain. Who was shot? Oh please, oh please, who was shot??!?
Woman on dark street thinks she’s being followed, pulls coat around her and hurries. Shot of her feet hurrying. Shot of his feet walking. Shot of her feet hurrying faster. Shot of his feet walking faster. This goes back and forth a couple more times until she’s actually running and he suddenly grabs her from behind.
(I never actually saw this, Harlan Ellison once wrote an article complaining that one of his well-written scenes had been cut and replaced with that. It sounds enough like mystery scenes I’ve seen that I believe it.)
This has happened in every “Friday the 13th” movie.
Then there’s the medicine cabinet trick. You can be sure her reflection will have company when she closes the mirrored door. Hackneyed but effective.