I added two new color blending mode layers in order to add brown (from sand) tones to the sky and green (from the water)tones to the wet sand. I chose to fill layers with solid color then reveal the colors by painting with low opacity white brush on black layer masks. Another method would be to just paint directly on a blank layer with a low opacity color brush. A third way would be to make two hue/saturation adjustment layers (adjust one for brown and the other for green), then paint on the adjustment layer masks to reveal only the desired areas.
Reduce layer opacities until there is just a hint of color toning.
forum discussion: http://forums.dpreview.com/forums/read.asp?forum=1006&message=26850142
original image by Kallias: