One of my favorite ways of sketching is to do blind, or semi-blind, contour drawing. In it, you try not to look at your paper at all, and not lift your pen, while you draw. You look at the subject, not the paper, and feel your way around and within your subject, as you draw with your pen or pencil. I was first exposed to this method in a studio drawing class in college and found it marvelous. When I do this while drawing a person, it connects me with the interior feelings of the person. It reminds me that the visual nature of the person is not just about ‘looking good,’ and that the success of a drawing is not in its photographic likeness. It also draws my attention to how we can perceive some of the complex life of a person even through outer appearance. It is, for me, a kind of spiritual exercise.
You may wish to try it. All you need is a pencil, paper, and a subject. The easiest to start with is yourself in a mirror. More details about this method can be found in a book by Kimon Nicolaides, A Natural Way to Draw.