Character Clues
Character Analysis
Actions
What matters isn't what someone says or the color of their skin, or even what kind of family they come from—what really matters is how they behave when challenged to act. Frannie and Jesus Boy both show that they are good people when they help Trevor up after he falls… even though he's been a pretty huge jerk to them. Samantha, who talks all the time about how religious and godly she is, doesn't move to help Trevor at all. This doesn't mean she's automatically a bad person, but it does show that talk is cheap and religion doesn't automatically make someone good.
Direct Characterization
Besides describing how people behave, Frannie also just straight up tells us about certain people, and what they're like. When she describes Trevor, for instance, she is honest about what he's like around other people. And guess what? He's kind of annoying and aggressive:
As the months passed and he kept getting in trouble for hitting people, we figured out that he had a mean streak in him—one minute he'd be smiling, the next his blue eyes would get all small and he'd be ramming himself into somebody who'd said the wrong thing or given him the wrong look. (1.32)
She also goes on to describe how smart and nice Sean is, and how Samantha is a great friend. Because Frannie's the narrator, we just have to trust her judgment—she's the one who has known these people for years, after all.