Just as singing starts with the ears and not in the throat, drawing starts in the eyes and not with the skill of the hand.

Singing and drawing depend on how our brain interprets external stimuli and the windows that make these stimuli reach our brain are the ears, in the case of singing, and the eyes in the case of drawing.

Training your eyes to correctly identify patterns of shapes and colors is essential in the begning. Without this skill, all the dexterity you can acquire with your hands will be drastically impaired.

Because we can't draw well what we don't see well.

Almost all the artists I've met who said, "oh, I'm better when I draw from my own imagination", actually had a hard time representing what they saw because they didn't make a good start in learning to draw.