How to act scary for a film?

Watch a few movies like The Shining or Halloween; Torrence and Myers both have something that makes them really unique in their acting... Whether it's Nicholson's perfected evil smirk and sarcastic/asshole attitude, or Michael's almost vacant and emotionless persona. Something as simple as a little twitch of your lips when your about to kill, or go all Darth Vadar with the heavy breathing... Just something small and different that can be memorable before you go for the kill, ever see the Grudge? That creepy croak sound... That's what I mean, just experiment with your character and come up with something insanely creepy/weird that'll make you scary.

be your person. Feel as if you really did kill your parents and seeking revenge. You also must remember that its the makup artist job to make you look scary.. And the directors Jon for your movements in camera. Your only worry is remembering your lines and such.. but just plat it out in your head or wear the costume and make up and act out one of the scenes from the film. Try diffrent jestures, facial expressons, voices, body movment, untill you scare yourself or one of the crew..