I’ve just discovered a great resource for teaching narrative technique: H. Porter Abbott’s Cambridge Introduction to Narrative (Cambridge Introductions to Literature), 2nd Edition (2008). The paperback edition is under $20 on Amazon.com (U.S. dollars).
Abbott writes clearly and uses examples that high school students will be able to understand. More arcane points are covered in sidebars, where they may be ignored if you wish. He defines terms carefully but avoids jargon. He is aware of all the various schools of narratology that have sprung up in the last generation or so, refers to them from time to time, but is not enthralled by any particular theory. His view is broad and tolerant, but he is not afraid, either, to take his own positions and defend them.
This is a great book to help students begin thinking about how stories work, instead of reading naively. Highly recommended to anyone teaching literature in Grades 10-12, and beyond.