Writing an Essay About To Kill a Mockingbird / Catcher In The Rye...?

I need to write an essay comparing and contrasting the relationships between Holden and Phoebe Caulfield, and Scout and Jem from To Kill a Mockingbird. I've already written a paragraph about how Holden/Phoebe trust each other, and Scout/Jem don't, but now I need some new ideas. Can anyone help?