We all fail at it. Don't feel like you are alone! I realized at some point that I was unable to change myself, or I'd take two steps back for every step forward. I started praying to God to change me, mold me as I could not do it alone. I started reading the Bible more. I noticed over time that I started to change and it wasn't due to my own effort. Some of the things I used to do I just don't do anymore - those things are repulsive to me now (and may it always be so!). The narrow path is a journey and there is no end until we are Home. Each one of us on that path has their own trail - tailored to what each of us needs. Parts of it will be painful, shameful, and incredibly humbling - but all of it is meant to hone and purify us. Look up! Seek God first! The rest will come in time.