02. Don’t be afraid to make random marks at this stage, and use a number of custom and textured brushes to suggest the forms. At least three brushes have been employed to describe the tree here, with the standard Hard Round brush used to draw the trunks. Keep this tonal stage on a single layer to begin with and think purely in terms of shape and areas of light and dark. step ow.

03. Now create a new layer (Cmd/Ctrl + Shift + N). This will be your initial colour scheme, so choose an appropriate scale of greens and start blocking in, being sure to set the blending mode to Overlay (in the top left of the Layers palette, next to opacity). The actual colours can be seen in the bottom right.

04. Now open a suitable sky image (you can download one for free from stock.xchng at (tinyurl.com/c5uho9) and select an area that will fit into the painting. Copy and paste this into your image and, using a soft-edged Eraser (Airbrush Soft Round is good) blend the edges. Go to Image > Adjustments > Brightness/Contrast and adjust the sliders to help integrate it better.