Try some “blind contour” — you place your pen tip onto the paper, then look at the subject and draw without looking down at the paper. As you look at the subject, imagine you’re physically tracing its outer & inner shapes, making one continuous line, like string. Each face here was a separate blind contour I did on the bus. I’m amazed that they turned out this legible; you can get some wacky abstractions from this method. Go wild!
(I also like modified contour, similar technique but you look down at the paper only occasionally.)