I think you could answer this question by looking at the different "roles" we see Atticus in.
- Father: consider how he treats his children when he deals directly with father-children lessons. He does not treat them like children in the way he talks to them, but he also does not let them see him worry or struggle with adult problems.
- Brother: when Aunt Alexandra (and Uncle Jack) Scout talks about "overhearing" conversations (which she frequently isn't giving the complete truth of the situation as a result). Nevertheless, when he is dealing with his brother and sister, he acts very differently than he does with his children.
- Neighbor: consider his attitude toward Mrs. Dubose. Also consider how he acts around his lifelong friend Miss Maudie. Both very different from Atticus as father, but also very different from each other.
- Lawyer: Scout and Jem see a completely new side of their father in the Tom Robinson trial. For Jem, this solidifies his admiration. For Scout, who is younger, she has mixed emotions of fear, pride, and confusion.
Through the different roles Atticus plays, and Scout's observations of these roles, the reader gets to see many different aspects of Atticus' character.