Andrew has a few teachings on the topic, but to summarize: focusing on your sin is a sure-fire way to keep sinning. Stop focusing on the problem, and start focusing on the solution. Whatever you focus on, will be what you become.
Gods grace covers all sin. So don't feel bad when you screw up, and don't think that God looks at you any differently when you do. Focus exclusively on seeking God. That is the heart of the matter. Everything else is just symptoms. You know what you did is wrong. That's the conviction. That's all you'll ever get from God. Guilt, condemnation, or inferiority are from the devil.
I defeated a 6 year porn addiction because I focused on God, and didn't feel bad about watching it when I did. Within 4 months, I realized I really didn't want to anymore. I still occasionally feel my flesh pull in that direction, but it's a single, solitary thought that I can easily cast down. I can only credit Gods grace, and time in His word. Because I tried myself more than once to quit, and it never lasted more than a month or two.
As far as devotion, I would encourage you to read Romans and Galatians. Both were written by Paul explicitly on Gods grace. Once you receive that revelation, everything will be much easier. Andrews books "A better way to Pray" and "Grace, the power of the Gospel" would also be great reads.
If you have the time and are close to one, Andrew has a bible college (Charis Bible College) with satellite locations all around the USA. They are evening classes, usually 3 hours a night, 4 nights a week. I am just finishing up my first year, and wow, that made a difference. I have grown more in the last 9 months than in my previous 19 years in the church. They also have online courses, but if at all possible, I encourage you to go in person. The relationships I've made, and the ministry I've gotten from talking to the directors at my satellite location have truly been invaluable.