Nobody taught Picasso how to paint - he learned for himself. And nobody can teach you to be a producer. You can learn the mechanics, but you can't learn what's right about a script or a director or an actor. That comes from instinct and intuition. It comes from inside you.
When I am seriously composing, sometimes a phrase will come into my head, a catch phrase. When I was writing pop songs for a few years, as a career, separate from my folksinging career, I used to write songs for pop singers.