I don't know what grade level you will be teaching, but a great elementary resource is a whole series of short books by Mike Venezia - each on a different artist.(about $6.00 each) I read these to 1 - 3 grades. The author did a great job of including what is interesting to kids, and leaving out the parts that aren't really appropriate for them to know. I think that you could develop teaching ideas from these books. One example - the book on Mary Cassatt led into a painting about someone the student cares about, and how they could show that.