We have used the "How Great Thou Art" series in our homeschool in the past. I love the layout of the books, and how Barry Stebbing breaks down the drawing techniques for children. Here, available until the end of November, is a Nature Drawing and Journal download for free.
If your homeschool experience is lacking in the area of Art, I highly suggest any of Barry Stebbings products. He has books available for all age levels.