A child's self-esteem is very dependent on you. As a parent you have the power to increase or decrease it with your words and actions. Research shows that self-esteem is prevented or damaged when parents do things like ridicule their children, make them feel ashamed, punish them for unsuccessful attempts and expect perfection or constant success, or when they seem consistently disinterested in them.
Be aware that self-esteem can also be decreased if you expect too much or too little of your child. This sends a message to your child that he is not good enough to please you.
You should also be careful not to expect too much of yourself as a parent either - this will only hurt your own self-esteem, and it may also cause you to expect too much of your child.