Once I have my final color plan, I open up my stash and pull out a variety of fabrics in each of the colors. Then I fold them and put them in a box vertically so I can see each fabric. Having them in a box makes it easy to move the fabric out of the way when I have to use the table for something else, and easy to see my choices when working on the project.
When an idea occurs to me, I write a note on the color plan and cross it off after I have done it. It helps me keep track of the little inspirations you get along the way.