Here's a list of things you should be doing if you decide to become a monster. If you:
aren't sore or aching in pain by the end of the night
haven't made someone cry from scaring them that bad
haven't had someone throw a beverage on you
haven't made someone think you are having convulsions/seizures
haven't sweated off your makeup halfway through the night
haven't dry heaved from pushing yourself past your limits
...then YOU AREN'T DOING YOUR JOB RIGHT. Being a monster in a haunted house requires inhuman levels of blood, sweat, and tears that you won't see in a lot of other jobs at the park. It's as close to being an actor in an Oscar-winning drama as you can get, meaning you have to make your audience believe you are a force to be reckoned with. It's not simply popping out of a closet and going BOO, but becoming something people will genuinely fear and be afraid of.
Also, do not, I repeat, DO NOT be afraid to act crazy. Sanity is all but forbidden at the Haunt. The crazier the better. Don't be shy or timid (unless a role specifically calls for that or you know how to make shy and timid scary); be loud and aggressive. Get up close and personal with them. You can get up to an inch away from their face and, without touching them, scare them silly as their personal bubble pops. They've entered your territory, and that means it's time to defend it.
One last thing, this is a team effort. It is a lot harder if a single person tries to scare a large group, although in some cases, you may be all by yourself and have to go rogue. But if the opportunity comes or you have other monsters to work with, by all means, WORK WITH THEM. Tag-teaming is a killer way to get people into the fetal position when they realize they are surrounded. Also, ping-ponging works fantastically with other monsters; scare a person and lead them to the next monster, they scare them and lead them to the next one and so on.
You (should) have the ability to work with veteran monsters, some of them are back for Round 2, others are almost living legends they've been here so long. Don't be afraid to talk to them to get tips, they are a gold mine of information and they will go out of their way to help become one of the greats. After all, the Haunt crew is like family. One big dysfunctional family.
Hope this works out for ya,
- The RingMaster.