Earlier I had decided to keep the value range smaller, but I see that it’s feeling too dull. I play with the Curves tool (Magic Wand> Curves) to add overall contrast. I begin to refine the modelling of my form in two ways. I use a large softer brush on a new layer to model the large shapes of the head, cutting away at this with an Eraser for any sharp edges. This, along with Lasso selections and masks, can also be a useful technique if you don’t have pressure sensitivity.