What is daydreaming? You have a desire but you do not have the faith that you can achieve your desire - that is what you call daydreaming.

You can control daydreaming by having a strong goal and believing in it.

Like the scientist who wanted to go to the moon and kept dreaming about it - for him it was the goal of his life but for others it was daydreaming.
Either you drop that it will not happen or you believe!

When you do not know yourself, your potentiality, you have no faith and confidence in your dream.

Once you have faith and confidence in your dream, it is no longer a daydream!!