@mrjunge @strix What finally "unlocked" sketching for me was the book "Drawing on the Right Side of the Brain" ( http://drawright.com ). It's not so much a question of dropping all theory, but of not abstracting details. Your verbal/conceptual brain has this tendency to see things not as they are, but as a symbol of the thing.

If you leave it in control when you draw for instance, an eye, it will not draw an eye as what an eye looks like, but as what it stores as an abstract representation of an eye. When you see, say, a chair, you don't take notice of the lines, colors, shapes of the chair. Your brain engages its visual part only as much as it needs to in order to identify the chair, then stops looking at it; you just know that in your representation of the world, there is a discrete object at that position that is a "chair". Maybe it will have registered a bit more information "nice chair", or "brown chair". Once you let the visual brain take over, you actually start seeing the world around you completely differently, in lines, curves, colors, shades, distances, instead of discrete objects. And the verbal brain can't really do much, anything it does when it comes to looking gets in the way; there's no specific word or concept for a specific line that goes like "this", and "turns like that" and such.

This is what I needed that book to help me unlock, and what makes drawing a peaceful, meditative experience for me.