Hi Phyllis. I worked in the art field and did traditional watercolors for years as well as dabbling in other media and photography. This gives me advantage of knowing how the media should look, although duplicating it in software isnt so easy. Ive never gotton to where i can start from scratch in Painter. ( or from a photo for that matter LOL)
Anyway what I was getting around to is that a good knowledge of what traditional painting looks like is, I think essential to trying to duplicate it on the computer. For those without an art background I would strongly suggest going to museums if available and looking though art books, both how to and on the masters.
And i must add that all the techniques I have found here have really helped me with photoshop.