Doug Wilson has some good counsel here. It is in his book, Future Men, so the first part is especially geared toward boys but the second comment is relevant for boys and girls.
“Another important principle is that of seeing small boys as future men. The way boys learn to deal with their various immature ‘passions’ will generally be the way they deal with adult passions. A boy who is not obviously learning self-control with regard to his temper, his stomach, his video games, or his school work is a boy who will still lack self-control when sexual temptation arrives. Many times mothers unwittingly train boys to mistreat their future wives through sinful indulgence of boyish passions.” p. 84.
“Fourth, a mother needs to realize that when she gets exasperated or annoyed with her sons, she is helping them to learn how to control or manipulate her. The drill usually goes like this: A son doesn’t do what he was asked to do seven or eight times. Mom finally gets steamed and flares up over it. Mom has more of a tender conscience about her annoyance than son does about his disobedience. She consequently apologizes, he magnanimously forgives her, and the quarter ends with him two touchdowns and a field goal ahead. The solution is for her to cheerfully require obedience from her sons long before annoyance is even a possibility.” p. 85