A detail of the foreground pebbles and sand. I've used an old toothbrush to spatter paint on to the sand to give texture. I started by spattering on a dark colour and followed this with a light colour, the idea being that the light 'droplets' will randomly sit on top of the darker ones to give the impression of grains of sand. Had I wanted to produce a pitted-looking surface I would have applied the light spatters first followed by the dark. I then pick out just a few of the more obvious blobs of light or dark and emphasise and refine them with the tip of a palette knife, which enhances the overall effect.