My three oldest daughters and I enjoyed Get Real -- About Relationships, by Elizabeth Crist. During this 40 day study we learned about teenage relationships. The study is broken down into eight weeks with a study a day for five days a week. Each study has scripture to read that goes along with the lesson, along with "Think about it," questions, a daily challenge, and a Get Real with God (we used this section for our daily journal).
Each weekly lesson covered a different type of relationship. Week two covered the relationship with ourselves. This one I felt was great for my teenage daughters because of the way the world is today. Girls struggle with their self esteem. Week three is very important as it covers teenage relationships with God and the importance of having God in your life. Elizabeth did a great job with this study. It is very thorough as well as right where teenagers are. They understand and can relate to each study.
My daughters have really grown in their relationships - especially their relationship with God. I would recommend this study to any teenager or even an adult who struggles in any kind of relationship.