The thing that I learned when I lived in the South, besides those already mentioned, is to have an answer to the question "Where do you go to church?" In St. Louis, we are infamous for always asking new people we meet where they went to high school. (On a job interview today for an associate attorney position I was asked that question.) When I lived in Little Rock, I learned that they ask the church question with even more regularity. I think I was probably invited to every single church in the metro area while I lived there.
(And I get my sweet tea fix these days at McAlister's.)