The previous post from Jo Ann reminds me of one of the best teachers I've had (I can't say EVER had because I had many many best teachers). I took as many of her courses for special education teachers as I could, and one was a course on teaching aesthetics. There's no special gimmic to teaching special ed, but Dr. Christoplos taught us many very basic things.
One involved teaching the elements of art using post cards. I used this with my inner city third graders and then took a few of them to the big art museum in D.C. They were able to wow surrounding strangers by walking into an exhibit and identifying the works with the artist's name. In some cases, they were able to describe which period the works were created. I had so much fun with this, that I brought my cards whenever I was visiting an art museum, even with adults. And a visit to the museum gift shop helped me expand my collection.
Here's a hint of what we did.
I'd start with very different works. Say, Audubon and Picasso. I'd say "Sort the cards into Audubon and Picasso. ... How did you know the difference?" Then I'd do the cards like flashcards which would give the kids practice saying the artists' names. Then I'd add another artist, say Rembrandt, and go through the process again. We would describe the differences ... subject matter, lighting, medium, perspective, choice of colors. Then I might introduce another work by one of the familiar artists and have the student guess who the artist might be.
Here is a work by Monet.
Can you find another painting by Monet?
(show the following post cards)
If the student chooses the wrong one, you might make a comment like "Oh that is a Matisse. I love the way its figures are kind of flat, and how there are fabric patterns and natural objects going this way and that in different directions and making your eye dance all round the picture." Such comments open the way to a later matching of Matisses.
What I like about this sort of teaching is that I didn't have to learn a whole lot of stuff before I started teaching. All I needed was the artist's name on the back of the post card, and maybe a date. The student can discover things that the teacher hasn't noticed, and each person can find his way through the art in a unique way.