I took an online Art class hosted by University Advancing Technology when I was majoring in Game Design. The teacher was Nan Pendarvis (surname used to be MacMillan) and the course was on 2D Design. The students basically just had to study the basic principles and elements of 2D composition.
Links regarding what was taught:Digital Web Magazine - The Principles of DesignIncredible Art Department - Elements and Principles of DesignAbout Art - Elements & Principles of Design
Goshen College Art Dept. - Composition and Design PrinciplesMakart's Gallery - List of the Elements and Principles of Design