Self-control is learned behavior, and all parents would like their children to have more of it. In order to learn self-control, however, children first have to learn to let others, such as parents, control them. Being able to follow instructions is a good example. First, children learn to follow their parents instructions; then, they learn to follow instructions they give themselves. The same holds true for following rules, which are more "formal" types of instructions.
For example, a parent can teach a toddler not to touch a household item like a DVD player by administering a small amount of discipline (e.g., a brief time-out) each time the toddler touches the item. With such a small consequence, the toddler will usually not learn the rule the first time around. In fact, the toddler will probably touch the DVD player many times and spend a lot of time in time-out during the learning process. But with enough repetition, the toddler will begin to make the connection.
It looks something like this: The toddler approaches the DVD player, but then veers away from it. Being close to the DVD player has begun to make the toddler feel uncomfortable because he associates it with the discomfort of time-out. Something quite similar happens with appropriate behavior, too. First, a parent uses praise to make the child feel good about doing the right thing. Ultimately, through association, the child begins to feel good about using the behavior even when the parent is not around.
So in the initial stages of teaching child self-control, the parent provides unpleasant consequences for inappropriate behavior and pleasant consequences for appropriate behavior. But as time passes, and learning episodes accumulate, the child experiences the unpleasantness or pleasantness on his or her own. When self-control is well established, the mere thought of misbehavior causes discomfort. This discomfort does not spontaneously grow inside the child. It has to be put there through learning processes that are established throughout the child's young life.
So, when a parent teaches a child to follow a simple instruction or rule, there is much more going on. That parent is laying the foundation for building the child's capacity to follow his or her own instructions. In short, parents who successfully manage their young children's behavior are laying the groundwork for children to manage their behavior (self-control) on their own.