Developing the sketch
I believe that the first line is perfect. However, the second line that’s added to an image can be flawed, because now you have potential accuracy problems. The more you add to your drawing, the harder it becomes to stay true to that vivid initial expression. So I try to be as accurate and considerate of these early marks, although expressive enough that it won’t be a constrictive base to build the picture on.
Establishing early contrast
I stop drawing lines and use a brush tool to establish masses. I find this more efficient for sketching out and seeing if things that work in my head will work on the canvas. I establish contrasts that will be necessary for the final composition, knowing that my end result needs to focus on the chess board. Faces don’t require spotlighting to draw the viewer’s attention.