Look into getting some books such as this to help with lesson planning and ideas. The Art Curator for Kids - 10 Great Artworks for Stimulating Discussion, Art Criticism Lesson, Talking About Art with High School Students
How To Market Yourself As An Artist: Part One Selling yourself is hard. You're all about the art, not the business. But you can't make a business of your art without the selling. Here are some tips for marketing yourself as an artist.