Hi!
Though I've never seen Halloween, I think I know what you're talking about.
I think the best bet would be to shoot with the camera shoulder-mounted, or otherwise bulked up... so you get that first-person perspective, but without TOO much of the jiggling and jarring that you would get if you tried to shoot with just the camera itself (assuming it's a consumer or prosumer, lightweight model)
It's a good idea to give the camera at least one point of contact to your body besides through your hands. For instance, if you're shooting with a viewfinder where it's held against your face, that will offer stability. Or if you're shooting with an LCD/monitor, then some other way to stabilize the camera against your chest, etc.
Hopefully some of those ideas help.
P.S. If you're talking about shooting as if through eyeholes in a mask, you'll likely want to shoot manual focus to keep the camera from trying to focus on the mask in the foreground.