Guest Post by R. Harlan Smith, he is a Water colorist and a Writer. For more about him click here
Tips for watercolor sky and water:
I use a Cerulean blue to get a matte (and distant looking) sky.
Use a wide brush to pre-moisten the sky area and wash with a light Cerulean blue, leaving a few unwashed slivers to represent cloud wisps. Avoid uniformity.
The sky is always lighter at the horizon.
Use Prussian blue for water.
Prussian blue, lightly washed over the pre-moistened area designated for water will produce a nice, reflective looking surface.