I being with sheer fabrics that I like and cut random shapes out of a piece. I glue those around my canvas with Novaplex. It's tough and you can really smooth out a piece of fabric with it. Then I sometimes do an overall wash of a particular range of one color. Blues, or yellows, or whatever. Then I begin to darken some areas which creates my values. The midtones are already there and the lights are created by adding the darks. Sometimes I may lighten more areas either with alcohol (rubbing some out) or adding a lighter color. Then I usually come in with a contrasting color or a sepia or grey to dull some of the areas that are too bright. Next is design. Are my shapes more rectangular or curvilinear. I begin to develop those areas. Now I check to see if there are eye grabbers. Or two shapes on the same plane or the same size. From there I see if there is a direction I am leading you to or even a focal point.
It's not easy but it sure is fun