Watch the Blues for Two online guitar lesson by TrueFire from Play Jazz Guitar 6: Soloing Approaches
Blues for Two - Call & Response is a video guitar lesson presented by Mimi Fox and is sourced from Jazz Performance.
In addition to listening intensely to great Blues artists and their recordings, an important and fun thing to practice is trading "fours" with a drummer, another guitarist, a sax player, singer, etc. This will help you develop a feeling for call and response and it's fun to try and answer someone else's lines. Listening to Gospel music will also help you learn this important musical concept.