I've found that you need to get down to their level and look them in the eyes to get around that. (Supernanny tip, works!)
No two kids are alike. And, things that work for nannys don't always work for parents.
Hell, things that work for one PARENT, don't work for another. My daughter acts awesome with me even when I take care of her all day for weeks, but she's a complete terror around my wife.