PAT: Fast demo by Pat of suggested color scheme for this image at Sheila's request.
Reminder: a simple grid of your reference photo will save you a great deal of time with your composition. You can always mask off a part of the image and make the grid only for that.
Also, if you work in other mediums, try fast sketches using those, too. You may find that a subject works better for you in water-soluble oils, acrylics, pastels, or oil pastels, as well as watercolor. Any effort you make in any of these mediums will add to your knowledge of the subject.