http://paintinglessons.wordpress.com/water-and-reflections/ - Complete training DVDs are available at www.lenhend.com
For painting reflections in oil or acrylic or house paint if you wish, this is the technique I have been teaching since 1976
It is a very simply way to paint water and reflections. First we paint the reflection of the sky then add the reflections of things on the bank and finish by adding the river bank and ripples where needed. The different layers of paint can be allowed to dry or you may paint wet-on-wet Remember, reflections come straight towards you.