In To Kill a Mockingbird, what "trick" does Atticus teach Scout about getting along with people?
Atticus taught her that you never really know a person until you "climb into their skin" and walk around in it. In other words, you've got to climb into their shoes and see things from their perspective. By teaching her how to understand the views of others, Atticus is preparing her to understand life in a unique and mature way.
This is particularly important considering the drama that will begin to unfold in the town as Tom Robinson's trial takes place. People who Scout thought were good will go "stark-raving mad" when the trial begins, because it involves race at the core of the subject matter.
Sterotypically, the South has always had race problems. While it is true that a lot of documented racial persecution and strife has taken place in the Southern United States, it is also true that all areas experience some sort of racial tubulance from time to time. This is important to note as one reads the story, so as to avoid forming a negative opinion of the South as a whole. Atticus even tries to explain that the people are genuinely good, but when race becomes an issue, their perspective changes nearly 100%.