When Annie Sloan first went to Art School, she was encouraged to keep a sketchbook. This was not just for sketching but also highly useful as a way of developing a visual voice and language. She used her sketchbooks to collect colors, pieces ripped from magazines and pattern making. She still does.
Plan the color palettes of a room, work out a piece of furniture, and draw little sketches. You can use the pockets to collect ribbons, fabric pieces and cuttings from magazines. Experiment with color combinations making your own mixes.