Suzy W. answered 10/11/20
Pre-AP English teacher with 16 years experience
I teach that the theme is a universal idea in a piece. If you were in my class, and we had read The Outsiders, I'd ask you to state one word the idea. Like the most important word. You might say heroes, brothers, division, hate, or some other word. Say you chose division. What do you see that supports this idea? What does the author do teach us about division? Maybe you believe " division does not have to divide" meaning we are all different but we can be unified. Does your theme fit other pieces of literature? Harry Potter, divergent, Hunger Games for example. If it's broad and general then it is universal.
Thesis statement is in a nutshell - the point. What is the point of the article? How do you know? Did they prove their point.