Consider a lesson plan you might use. Which metacognitive skills/abilities are involved as students gain facility/knowledge in this domain? Think of an activity or lesson component that explicitly teaches one or more metacognitive and one or more problem solving skills.
I just found the BEST article in the universe that relates to this topic. It is a study where they two compared classrooms of third grade students. One class used metacognitive teaching techniques and one did not. They compared the artwork of the two classrooms made during their art time and found that the students in the metacognitve class "understood the thematic nature of art, generated more strategies, and developed a solution clearly related to their theme." The students were given a theme such as friendship or happiness and asked to create an art piece concerning their theme. During the planning process of making the work students were encouraged to think aloud about their theme.
The teacher that was incorporating metacognitive skills in her classroom did so by encouraging a "culture of thinking." She did thinks everyday that raised students self awareness, especially about their own thinking and focused on planning and problem solving. This study suggests that art teachers and classroom teachers should work together to increase the metacognitive skills of the students.
So if I was going to make a lesson that would encourage the students to gain metacognitve skills I would definitely focus on planning. I would have students do a lot of sketching before the create a product and talk about their work with me and other students. I would give students a theme to work under but not be too specific so that they their work does not end up all looking the same. OR I could let the students choose a theme at the beginning of the year and keep a process/sketch book that explores their chosen theme. This way their art is relevant to their lives and they are doing a lot of self reflection.