So... you want to be scary?
Sounds kinda silly, doesn't it? Doesn't everybody know how to be scary? Well... in a word: No.
How many times have you been to one of these walk-thru haunted houses, only to be repeatedly startled or chased... but never truly scared?
The first thing you need to understand is that there is a difference between scaring someone and startling someone. It is easy to startle someone... just jump out and go, "Boo!" or make a sudden loud noise.
A good haunted house is like a good recipe. You have a carefully balanced mixture of ingredients. Chases and "in-your-face" appearances can all be useful and fun parts of the experience, but a haunted house with no suspense or chills is about as much fun as a bowl of salt.
When a person is startled, they react without thinking. They will probably yell or scream, and perhaps bolt for a door. They may even punch you, but that is just the "fight or flight" adrenaline reaction.
But to really scare someone, you have to give them time to think. A person gets scared when they have time to think about their situation. Your victim's own imagination is your best ally, and all you have to do is give it some material to work with and a chance to take over.
In the better haunted houses, the actors and directors know how to give you a chill they can build suspense on, and induce a sense of dread. They know how to let the victim's mind produce worse monsters than makeup and lighting alone could manage.
Check out the links below for some useful scary techniques. All of these have been used successfully in the Haunted Theater.
Being scary is so much more than "jump out and go Boo."