We have had success with the Strathmore Learning Series books. We’ve only done the colored pencils and the watercolors, but they do have some on drawing. There are free video lessons online for each lesson in the book. They recommend good supplies.
One daughter benefited quite a bit from the “Drawing on the Right Side of the Brain” book and workbook.
All of my kids have used Mark Kistlers online drawing lessons. I think a yearlong subscription costs about $50 if you purchase through the Homeschool Buyers Co-op. Though he teaches cartoon style drawing, I was amazed at how much it improved all of their drawing.
