Us humans are something else. As creative beings we dumb down how the mechanics of the process is explained in a kind of humility. Artists run in the family and I don't know where the genes for art came from. In my book there is genetic potential or probability and environmental happenstance and some kind of inner drive. Copy that, express that, "Honey, we don't mark on the walls in this house!" "Dear, we better get him some paper and crayons." Of course they do so but they don't put the paper on the walls where he likes to draw. In a coloringbook, scattered pages on the floor or a proper desk or table. You got to control the energy to make a mark.
Control from the mind to the hand. Why some folks can draw what they see, some see it but are denied the ability to draw it. No we all don't have the right combination of stuff. Drawing can be learned to a point. You can learn the mechanics and stir up a motive force. In the end either you have it or you don't and that is in degrees.
We are taught that the mind is everything, but the brain is not the whole mind. The whole network of nerves from the clump in your head to stub sensors in the tips of your toes are also the mind. Muscles have memories. Emotions are imprinted in our character and motions are imprinted in our muscle memory. A boxer's range and speed of motion is all visible, his trainer hones and sharpen those skills. Harder it is to train the motive force that makes him breach his opponent's sphere and retract into defense ready to strike again. Reaching a little further, a little faster and control, timely strikes, timely withdraws.
The artist can learn all the tools, but what is needed is the muscle memory in the hands and wrist. Drawing a circle over and over till it's second nature. I have problems drawing the human figure because I have not practiced that. I can draw an electrical circuit in a second, that my muscle memory knows well. I can draw a straight line and a perpendicular one too. I know drafting, freehand drawing is a different matter. This new physical workout craze is on spot, where they vary the exercises so they are not routine. You blast muscles from many different angles. If you are a computer artist, go take a freehand drawing class or a drafting class. The motive force is the same but the reasons and procedures will give you muscle memories you didn't think you had. Then when you hone in, your skill set is wide yet focused because what you practiced your body remembers. It is now at your command.
Every line is important when you draw but not for the finished piece. I watched many artist working. I think they put too much effort into their work and the final piece looks simple compared to how much work goes in. Why not just start drawing the final piece. I have done stuff where I drew a line and that was the finished work. I always wanted to improve upon it. In the process of the draw, many lines shape both the idea and the form. When they are solid, then lines are taken away or covered over. Guide lines, sketches, scratch efforts are all the way we think, work it out. We draw upon our muscle memory to shape what we see. Just think, if we did this on paper how many miles of lines we draw. On the computer it less messy and wasteful of materials. I want to tell people, the computer is not that big a shortcut in the art process. Actually you have a very wide pallet of resources and techniques, you can't do them all, just what you know. The process is the same when you apply what you know, that is what your mind sees and your muscles remember being triggered by the motive force. Tell your friends, "it's all in the wrist, or art runs in the family".