Tim Lane & Paul Tripp, in their helpful book How People Change, suggest that there are 5 Gospel Perspectives that shape lives.  In other words when we understand these principles, and regularly consider our own lives in relation to them, we see change.  These principles, considered collectively,  cultivate the best conditions to see fruitful sanctification.

1. The need to recognize that God calls for ongoing and continual growth and change in all of us.
2. The need to understand the extent and gravity of our sin.
3. The need to understand that the heart is central; that behavior and attitude is a reflection of the heart.
4. The need to understand the present benefits of Christ.
5. The need to live a Lifestyle of Repentance & Faith

If you are curious, you might want to check out an interview with Lane & Tripp, where they describe their motivation for writing the book, and explain how to apply the gospel to real life to bring about real change: Interview