I found a process I like for sketching people. I use pencil first… not even a drawing pencil. I use a mechanical pencil with soft lead. As my subject shifts, I sketch the limbs in their changed position. Sometimes this happens several times. I use pen and ink to emphasize the strong lines and leave the pencil tracings and smudges. I leave my options open to clean up the composition and perhaps even add some color at some later time.