[gmku]

It's written in the first person. Think about why the author chose this point of view and talk about that. Most obvious reason--Caulfield is talking to his psychiatrist; use that as your starting point. Explain first why this is the case--I can't remember the clues, but I know they're there. Then talk about the advantages of using this POV for seeing the world as Caulfield does, and so on. Go wild. At this point, since you've got a good start in basis of something very true about the book, you can go out on limbs and test ideas even if you can't fully support them. You'll impress your teacher.