I have no interest in art and was surprised when my eldest became fascinated by drawing at the age of 10. She figured out how to teach herself. These are the steps she took:

 1. Borrows books from the library on how to draw Anime characters. Everything is broken down step by step. The figures are simple. Does this for a year.
 2. Uses birthday money to buy a book on how to draw dragons. Works through the examples over the following year.
 3. Learns perspective drawing at school. Continues to practice on her own.
 4. Mom springs for summer art classes. Kid learns to mix colours and draw from life.
 5. At 15, sets goal of drawing every day. More practice.
 6. Mom springs for more art lessons, including human models (minor ethical crisis at nude models. Nothing bad happens).
 7. Kid uses birthday money to buy books full of photos - like plants or motorcycles. Practices drawing things.
 8. High school offers art courses; kid attends. Learns various media.
 9. Kid currently 23 year old software engineer. Draws whatever she wants from life or from her imagination. 

So it took over 10 years of frequent practice. She started with how-to books; progressed to copying from photos; then just started drawing what she saw. She got a small amount of paid instruction, and several courses through the school system. It just takes a tremendous amount of patience and attention to detail. If the kid doesn't want it, it's not going to happen.