Conversational and Blunt
Lily directly addresses the reader at several points, giving you the sense that she is telling you a story. Her blunt, straightforward style contributes a lot to the wryness of her tone. You can see both at work in her description of her father's attitude toward her reading:
Whenever I opened [a book], T. Ray said, 'Who do you think you are, Julius Shakespeare?' The man sincerely thought that was Shakespeare's first name, and if you think I should have corrected him, you are ignorant about the art of survival. (1.103)
She says a lot without using a lot of words; you can practically see the eye-roll she was giving when she had these thoughts.
Again, as with the wryness of her tone, you get a great sense of Lily's personality from her writing style. First of all, she's clearly got a good sense of humor. Second, her bluntness and conversational style suggest a general interest in cutting right to the chase and calling things as they are. She wants to tell us a story, simply and without a lot of bells and whistles, and her storytelling style reflects that desire.