Each child is different, but the thing that worked with all of mine were clear and consistant boundaries. All of mine learned right away I did not respond to fits. If you're going to throw a fit, you'll do it in your room. The positive re-enforcement works wonders. Children are clever little things. They will push those boundaries as far as they can. We had our niece and nephew for several months. Before living with us they had never learned the word no, they had no structure in their life. It was utter chaos. With the two of them that gave me six children under the age of 7, we had to have rules. They came around literally within days. But if their father ever came to visit, watch out. They reverted immediately back to their bad behavior. My BIL asked why they misbehaved with him. Because he let them and because he wasn't paying attention unless they were misbehaving. They will get their attention one way or another, why not make it a pleasant experience?