This looks like a very interesting assignment.  To Kill A Mockingbird is a loosely-autobiographical novel--meaning that though the characters and situations are fictional, they are based on people and events in Harper Lee's life.  (Harper Lee's father was a lawyer, like Atticus; Dill's character is based on Truman Capote, Lee's childhood friend; Tom Robinson's trial is based in part on the Scottsboro Trials; and Maycomb, the fictional town in Alabama in which the novel is set, is based on Lee's hometown of Monroeville, Alabama.)

Charles J. Shields published a very thorough biography called Mockingbird: A Portrait of Harper Lee which examines Lee's life and its influence on her novel. 

I hope this is helpful!