First you learn about it

Many art students think ...with a little bit of practice, they can do painting well, like a professional artist. But what will happen is opposite. They never become good.
Why..?
The reason ...ignorance.
They don't know about the nature of subject.
When you don't know the nature of subject  which you want to learn, how do you do painting well? so if you want to do painting well, first you learn about it. Then be a dreamer. other wise it leads you to frustration.