Of course, if your interests are at the college level, your field is limitless. Indeed, you may teach anything you enjoy a lot. From teaching one on one, you will progress to teaching the entire class. Each lesson may be discrete and independent of others. You will get considerable feedback from everyone.
Most students feel themselves improving almost by the minute.
You are required to go over your mini-lesson each week with someone outside class before you teach your lesson before the class. Anyone may serve as your student - someone in this class, another class, roommate, friend, etc. You do not have to meet for a long time, but you must meet and teach. It is assumed that the readings in any given course may serve to further the aims of the course. Virtually everyone - parents, teachers, scholars, etc.