For example, if your teenage child prefers to sleep in rather than getting up at a decent time explain to him how this can affect his employment, college grades and ability to catch the bus on time. The goal is to get him to see why he would want to make a change. Make that your first and final lecture. With a view that the child has to exert himself toward the new habit, do not interfere when it isn't necessary. Help as inconspicuously as possible.
Habits ordinarily take about six weeks to take shape and become permanent.
Then they are habitual and will not need additional work. After the bad habit has been replaced by a good habit you can target a new habit. Consciously apply yourself to the new habit for a month and a half. Be consistent during that time frame and at the end of it you'll find you have a positive change that is now habitual. Mother will pick up the habit of training her children in good habits.