After a trip to the grocery store or farmer's market -- try a few, or all, of these exercises. Use your sketchbook for the drawing, and use scraps of watercolor paper for the color exercises -- or a watercolor sketchbook, if you have one. . .
1) Cherries in a Box -- With a pen, draw any fruit and whatever container you brought it home in. Add a little color with watercolor or colored pencils. Then, write in pen, where the fruit came from and what day it is. Make the words part of your composition . . .