How does a person who is trapped in sin repent and fight against that particular sin?

Dennis Gunderson explains in this video that if a person is trapped in a life of sin and does not know how to repent and to conquer a particular sin, they need to first recognize that repentance is going to be a gradual change.

They must resolve to live a life for the glory of God and understand that they will be constantly having to repent. It may be a long process. A high level of accountability may be helpful. Additionally, it is important that they are transparent with other godly individuals regarding their struggle with sin. 

1 Thessalonians 5:23 (NKJV) – ‘Now may the God of peace Himself sanctify you completely; and may your whole spirit, soul, and body be preserved blameless at the coming of our Lord Jesus Christ.”

If someone comes to me or another pastor and says, you know, I am trapped in a life of sin and don't know what is involved in repentance. There are so many answers that are going to be pertinent to that because a lot will depend upon what the sin is and how long they've been entrapped in it, how deeply embedded this lifestyle is. But one of the things that I would encourage someone like that to is to recognize that even making the most decisive break and the most sincere efforts at repentance, it's going to be a gradual thing. If they've got a lifestyle to be changed, they have got to, while on the one hand resolving to live life completely to the glory of God, they've got to understand this is going to very possibly be a three steps forward, two steps back matter. And that I'm going to constantly be having to redo, restart, rediscover new areas in which I thought I had put this sin to death and I discovered that I really have not, that it's infected different departments of my life in deeper ways than I ever imagined.

This is why Christian counseling, I suppose, is so important in that counselors need to be well trained in the Word because we need to be able to plummet the depths of what's in the hearts of men and help them recognize the tentacles by which sin reaches out into all sorts of areas of their lives. So I would exhort such a person at the same time to be fully resolved to give their life to God and yet patient with their own stumbling progress as they begin to do this. A high level of accountability I think is extremely helpful as well. If someone is going to be serious about repentance, it's important that they be transparent with some godly individuals with whom they can share how they're doing, if the struggle is going well or not, and get input from others that have been down this road.