My 2y5m old daughter speaks rather well for her age, but she keeps using 3rd person in almost every situation. Whether she speaks about herself or people she addresses to, she uses third person: not "I want to read" but "Sonya wants to read", not "You smile" but "Papa smiles" (while talking to me).
Showing her directly who "I" and "you" in a conversation are fails so far: she's not getting the relative nature of these labels and says "I laugh" when I laugh and "you laugh" when she laughs. Watching other people (or cartoon characters) speak to each other also helps little: she only gets interested in the point of the conversation, not the grammar.
What are the good approaches to teach her ways to understand and use first and second persons in speech?