It is important to understand that everyone is perfectly loyal to their own moral convictions, albeit they may not not be consistent moral convictions. The main reason one fails to overcome an addiction is that they are not convinced that it is an actual problem for them now, even if they realize that it is harmful and will become a problem in the future.
The main part is to realise that you are yourself responsible and can stop whenever you want and you have a "will issue" .Their are mainly two effective stradegies to control an addiction that must be followed hand in hand. First is to physically flee temptation by avoiding activities that open gateways to it and also be busy in other activities. The second step is to learn how to be bored and do low-dopamine activities like reading, bird-watching, etc. as to be able to reduce the level of stimulation you need for enjoyment.
One major hurdle is the tendency of an addict to rationalize his addiction. He may act like he wants to stop, but he is unable due to the chemical reactions of the brain. The best way to stop an addiction is to go 0% down the road, not reach 50% where you have already given consent to your addiction in a perverted fashion. In this condition, he is a victim of his own pscyhology(I would cover the topic of enjoyment in suffering in some other article). He wants to enjoy his addiction without the guilt that comes with accepting that he is responsible for his actions.
One such reasoning of many such individuals is to dehumanise themselves and treat humans as not a structure of a whole different from its constituents but as elementary evolutionary guided dopamine robots. This also helps to avoid responsibility, by making the common mistake of thinking that reality if 100% coherent with our "logics"/"science".(This is where reddit style atheism emerges)