Never ever scream or raise your voice from another room if you're trying to find out what your child is doing. Always, Always (I repeat, Always) get up and go to the room/area where your child is~~Quietly! If you follow this rule, they'll never know when you're watching them so they're more likely to behave! It's that simple. Never ever give them a warning that you're wondering what they're doing. (Of course, if you're trying to give them notice on purpose, by all means, but as a rule...don't warn. Believe me, they'll be much less likely to do something they shouldn't.) Viola!