Blocking out the base shapes

Before I start filling the base shapes with colour, I merge all the layers with lines. I’ll be working in greyscale mode, so I reduce the lines’ saturation by going to Adjustments>hue, Saturation, Brightness>layer. I select the base shape following the silhouette, using the Selection tool with the Freehand option. Then I pick the 6B Compressed Charcoal and fill the base shapes with a few variations of light grey.