Analyze the warm or cool qualities inherent in natural materials and exaggerate them. Repeating colors and values from the site itself in your design process will help to anchor the structure and give it meaningful placement. Take photographs as additional design information. Black and white photos can actually assist your design process by easily establishing tonal values, to which you can key your various color considerations. Take notes regarding your responses to the site at different visits.
Color is the means by which form initially reaches the human eye.
Develop various palettes from your information and refine them. Give yourself time to work with the various palettes, testing them out with color chips, photos and drawings. You can then apply your various color palettes to these tracings with colored pencils, gouache, or colored papers. Remember that the size of an area of color is a strong factor affecting your selection. It is not possible to know ahead of time exactly how a given color will appear, but bright colors tend to increase in brilliance on larger areas, and softer, paler colors can fade out almost to nothingness when enlarged to architectural proportions.