Everyone likes being in charge of something, even something small. Adults and children alike need a sense that something in their world is within their control. Therefore, if you want your children to exhibit responsible behavior, put them in charge of the exact behavior you want them to display.
For example, suppose you have a school-aged daughter who is always getting up from the table during dinner, thereby disrupting the environment you want to maintain during mealtime. In this case, think of the exact opposite behavior of what your daughter is doing and put her in charge of that responsibility. You could say, “Hanna, I need your help. I want you to be in charge of having all members of the family remain seated during dinner. Can you handle this?”
When put in control of something, children will always perform the appropriate behavior because incongruity (doing the opposite of what the person is in charge of) is very difficult for young people. This approach to changing behavior immediately is foolproof. If it doesn’t work, reflect: Did you think of the exact opposite? Did you use the exact wording of putting the person in charge and phrasing the responsibility in positive terms?