How do I start thinking like a teacher?

To start thinking like a teacher I need to understand why I am doing assignments other than that they were assigned to me. I need to start asking my self, why did my teacher choose this passage from the book to read? Or why did my teacher set the classroom up in the arrangement? Just start watching my teachers and trying to figure out why they do the things they do and how they are helpful to different learners, or in some cases, not helpful. Mostly I just need to study how my teachers teach and try to put myself into that mind frame. When I am in class I should be asking my self "what is the advantage of watching this movie?" or "Did that class discussion help further students knowledge by sharing their ideas with each other?". I need to start visualizing how I would do things in class and think every class how to be the teacher not just the student.