Begin by explaining to students that the theme of a story is the underlying message or “big idea” the writer wants to communicate to their readers. Invite students to reflect on what message or lesson they think the author wants them to understand or learn from reading their book and then go back into the text to find examples of how the words (and pictures communicate) the theme. End the conversation by asking students why they think this theme is important or why the author might have set out to write a book to share this message.
Additionally for 6-8:
Invite students individually or in small groups to identify what they consider to be the theme, or underlying message of the text and gather evidence of how this theme is revealed to the reader through, character, conflict, plot, etc. This resource from ReadWriteThink.org is a helpful starting place.