Examine the level of the art class you will teach and the average age of students. Determine what amount of skill they should develop by the end of the year and the progression they should make and what they should accomplish artistically.
Calculate how many lessons you will teach before the very last one. Write down a list of the concepts or subjects you need to teach. Determine the maximum amount of time you have to spend on each one.
Organize the order in which you will teach the concepts or subjects over the course of a year. Make sure that each concept follows the next in a reasonable fashion. For example, a few weeks spent on Monet and impressionism would be a good preface to studying Matisse and the art of collage as both artists and techniques use a method of combining smaller elements to create a larger whole, or image.
Find historical or modern-day examples for every concept you teach. Make sure that you are able to explain very simply to your students the history of each concept or technique, and have a picture of an artist or artistic piece which is an example of that genre. For example, if you were teaching pop art, you'd talk about its emergence in the 1950s and show them some of Andy Warhol's paintings, before moving on to the project, which would probably be a lesson in making pop art images.
Make a list of all the supplies you'll need and submit them to your school or department, or buy them on your own. Keep the receipts and submit them to your department for reimbursement.