When I would bite my nails, instead of saying, “oish, I shouldn’t have done that” I would say, “I can’t believe I was Michalel Shabbos”. That made a deeper imprint on my subconscious, and eventually would trigger my consciousness when I was about to do it. When I think about it as nail biting, it doesn’t sound so bad. When I label it as Chilul Shabbos, it becomes something to avoid.
Then I had popa administer a few sessions of CBT therapy . . . and the rest is history.