How do I track a theme through a text?

Think about key scenes in the text where the theme crops up, and try to pick out quotes that you think best demonstrate the theme.

For instance, if the theme is voilence, don't just think about scenes of physical violence, but think as well about characters who speak violently, the violent thoughts of characters, and imagery or descriptions that might suggest violence or foreshadow future violence. Equally, you could think about moments where violence is prevented, or repressed.