It depends on what your addiction is or what your self-destroying behaviors are. If it’s cigarettes switch brands – some are more addictive than others and it’s much easier to quit. Also, since your body is a closed system there are behaviors and addictions which support each other. It may be necessary to question multiple things in your life which are fostering one another to make the one seem like a much more staggering problem.
In general look around you and decide what is the result of your habit or your compulsion. Think back to how you behaved before this thing entered your life. Focus on the thoughts and behaviors that made you strong. Next begin clearing away the clutter and things which are associated with the negative behavior – be it actual clutter or the items which make it easier to sustain that habit. In this way you can strengthen the parts of you which are still there – the ‘you’ which you desire. Also you are making it more difficult to ‘see and remember’ to do this thing.
Another way of going about it: If you’ve been thinking about changing this thing for a while you have probably noticed certain things which seem to trigger or prevent your changing. Acknowledge these things as preventable (going to the pub for a drink) and know that, even though everything about them isn’t wrong, there may be some reassessment or changes on your part that can be made. Take a break from the environment or remove that thing from some place in your life – a sanctuary of sorts. After a break it will seem strange to get back into the same groove and the change you need to make will be easier, more controlled.
In closing, it’s not so much stopping one thing as starting something else or putting more emphasis on something you already do. By changing your environment you are also changing who you are in relation to the thing. It may be that you find that this is an ineffable part of you – something trite, laughable or even beloved by those around you. It may be that you should change with no delay. Like now. Right now. Not tomorrow. Now. Get it done. Do the other things which you’ve been putting off to do this other thing – look -things are getting better already! :)
Otherwise, the album Baby Darling Dollface Honey by Band of Skulls has a lot of the thoughts, the emotions I feel when I want to make a change—give it a listen.