Your watercolor painting will go faster and your results will be fresher and stronger if you plan your painting. You should be willing to spend as much time on your painting plan as you spend on the painting itself.
Take the time to make a value sketch in three shades: white, grey and black. When you have a strong, simple value pattern composed, annotate the sketch with numbers and notes.
Start with one for the lightest light. Make notes about what colors you will use, whether you will wet the paper first and where, edge quality, negative painting, masking, and so on. Divide your notes into three sections: lights, mid tones, and darks, so that you will preserve your value pattern. Indicate at which points you will stop and let everything dry. Here’s an example:
Lights: 1. Yellow all over, wet-in-wet, lightest at top. Soft violet and orange textures. Let dry. 2. Sky blue with soft edge at hill top. Let dry.
Mid tones: 3. Winsor blue/gray shadow, rattlesnake grass profile on top, scrape out light grasses on bottom. 4. Ultramarine/gray/tan shadows, more variation, dark grass profile on top, drybrush edge and scraping on bottom. Blue green to green trees above hill, soft edge underneath. Paint around and scrape out sky holes Let dry.
Darks: 5. Trees darker at bottom, dry brush textures, twigs, branches suggested. 6. Tree trunks & rocks are darkest dark.