Answer-ish:
Hi, I've never read this book but I can help you. First, find the theme of the book, the theme is an idea the writer wants to convey, such as compassion, courage, life and death, ect. Second, apply the characters to the theme, what do the characters do that portrays the theme. The characters actions can motivate a drive in a story. Where to look? The changes your characters undergoes from incident and the climax, seldom defines your theme.
sorry to hear you have to deal with trolls, you can always report them :)