The key to turning painting into an open-ended project is to start with minimal instruction. A brief introduction to mixing paints and cleaning brushes is all that is needed. Leave the type of paint medium and the subject matter up to the student. Oil paint, watercolor and other paints can be used at the student's whim. Open-ended painting encourages students to mix paint mediums and to experiment with a variety of styles, based solely on individual student desire.
Craft projects offer a perfect opportunity for open-ended artistic expression. Provide a variety of basic materials ranging from colored craft paper and glue to beads and objects from nature; then encourage students to develop artistic craft projects and choose the supplies that best suit the projects they have in mind. You'll find students creating numerous artistic projects from these items, including picture frames, birdhouses, collages and decorative wreaths.
Provide pencils, pens, chalk, charcoal, markers and colored pencils to the class. Avoid suggesting what your students should draw and encourage the exploration of various drawing tools to help keep each student's work as individual as possible. If students want to blend painting techniques with drawing, let them. Open-ended art forms should include as little instructor interference as possible.