My ideas usually start out as small rough thumbnail sketches. The arrangement of shapes and values in a composition is one of the most important parts of planning an illustration.
Here is an example of a poster project in the beginning stages: very rough sketches and experimentation with the basic layout, type treatment and color:
After I choose one idea the drawing is refined and more color options are explored:
The final illustration is painted with water color and acrylic before being scanned so the type could be added:
Sometimes I don't feel the need for so much planning and go straight from sketch to painting the final:
The Swallow and the Other Birds started out with a farmer holding the net. I later changed the idea to just be a net holding the birds.
Next I decided on 12 different color rules for the hummingbirds and planned where they would go in a color pencil study:
I had already painted the birds in the final piece when the idea came to me that the net should be growing out of a hemp seed