Lessons are 30 minutes long, once a week, and are taught out of my home. Each lesson consists of scales (finger warm-ups), musical theory (reading and writing music), and learning songs.
I typically have students working on 2-3 songs at a time. Each student is given a spiral notebook that contains any notes and assignments from each lesson.
Lesson time is instructional time, not practice time. I require my students practice all assigned work (scales and music) five times a day. That way, when they come to their lesson, they can pass off the previous music and progress to the new music. This makes the lesson much less tedious, and also makes it so that the lesson time is not as long.