In the book, how do different characters learn to empathize?

To show empathy is to understand the feelings of others. Many characters in To Kill a Mockingbird learn empathy during the novel. In chapter 2, after a rough day at school, Atticus advises Scout by telling her, "You never really understand a person until you consider things from his point of view." Scout learns to apply these words of wisdom in her understanding of Boo Radley. While he is terrifying to her in the beginning, she learns to understand him. Near the end, Scout recognizes that to bring attention to Boo for his role in rescuing the children from Bob Ewell would be "sort of like shootin‘ a mockingbird." She empathizes by showing awareness of Boo's feelings and personality.
Jem also shows empathy. Each time the word "guilty" is read at the end of Tom Robinson's trial, Scout recalls that Jem's "shoulders jerked" as if he experiences pain. Jem is upset about the verdict and becomes quite emotional. As the son of a lawyer, Jem is convinced that Atticus effectively proves his case that Tom is innocent. Once he hears otherwise, Jem tells Atticus, "It ain’t right." Jem empathizes with Tom and knows he has been treated unfairly because of the color of his skin.
Dill is another character that feels empathy for Tom. During the trial, Dill becomes so upset that Scout has to take him outside. Dill doesn't like the way Mr. Gilmer, the prosecuting attorney, speaks to Tom and calls him "boy." Scout attempts to help by telling Dill that Tom is "just a Negro," but Dill says, "It ain’t right, somehow it ain’t right to do ‘em that way."
Atticus remains a caring and empathetic man throughout the story, even showing empathy for Mayella Ewell. Although he knows that Mayella falsely accuses Tom of rape, Atticus understands that Mayella's life at home is difficult. In chapter 23, Bob Ewell approaches Atticus and spits in his face. Angry about the way in which Atticus handles the case with Tom, Bob threatens him. Atticus explains to Jem that if Bob "spitting in my face and threatening me saved Mayella Ewell one extra beating," he will accept it. Atticus shows concern for Mayella and the other Ewell children.