From Aunt Alexandra, Scout learns the basics of how to be a lady, but she learns two more important lessons. By the end of the novel, Scout learns how to see the good in people who are flawed. She learns this through her acceptance of Aunt Alexandra. She realizes the positive sides of who Alexandra is on the inside, despite some of the ugly comments Alexandra sometimes makes. By the very end of the book, the reader and Scout both see that Alexandra cares for Jem, Scout and Atticus in her own way, the only way she knows how to. Scout also learns from her, the value of loyalty to your family. This is clearest when Alexandra and Mrs. Maudie team up in their own discreet way against the ladies of Maycomb to defend Atticus.
Dill represents childhood and innocence to Scout.
From Calpurnia, Scout is essentially raised colorblind. She loves and respects Calpurnia, despite her race, just as Calpurnia loves and respects her. She learns that people should not be judged by the color of their skin. She also learns about the proper ways to behave and always treat guests with respect (look at the section early on in the book where Walter Cunningham comes over for lunch). When she attends church with Calpurnia, she begins to learn the nature of the racism and that the community and world at large does not offer Calpurnia the same opportunities that it offers her, since she is white, and she begins to realize that this doesn’t seem fair.
From the people of Maycomb, Scout learns about you can’t judge a book by its cover. People are not always what they seem. For example, Mrs. Dubose seems mean and cruel, but underneath she is strong. Mr. Dolphus Raymond appears to be the town drunk, but really he is sober and just wears a mask to live life the way he wishes.
I think what she takes away from all of this is that the world can people can be so beautiful and so ugly at the same time, that goodness does not always win, but that you must always defend what is good and right. She learns that innocence must be protected at all costs.