Help for a parent of a defiant child

So far I think a parent of a defiant child can get some really good advice from The Total Transformation Program. In it James Lehman explains how it is not effective parenting to renegotiate with your child after your child has done something they shouldn't. I agree. Children learn by example and repetition. If you tell your child they can't have an apple until they wash their hands, but you don't keep to this, they will know you don't mean business. It's even worse when you keep repeating this type of lax parenting. You still give them allowance even though they don't do their chores. You tell them they need to call you if they're going to be late for dinner, but they don't, and you don't give them a consequence. You tell them if they hit their brother they can't have computer time. Then they hit their brother and you try giving them the consequence, but they complain and complain until you say, "Fine. I'll give you a second chance, but don't do it again." By doing these things you are showing your child they are the boss not you. They are the ones in control. By renegotiating with you they control what will happen. Kids aren't dumb.