The child's mind is still a lump of loose clay , waiting to be shaped into a good pot.
So some kids tend to have an overwhelming feeling of superiority complex in them.
Narcissism maybe a built in quality of a kid.
The way to prevent it is by making him a down to earth human. The kid is needed to be taught principles of humility. Being a humble human being should be a very important aspect for every person on this earth.
They have to be taught storied with great Morales of humility and being a better human.
They should be taught all principles and morales of equality and equity. They moment when they are taught that everyday and instilled in their minds only then will they learn to forget the superiority complex.