The best advice I got on breaking a bad habit is that you can't do it by ordering yourself "don't do X" which takes will power and teeth-gritting effort. Any success with this method will fail over time. The problem is that it is like telling yourself to not think about pink elephants which makes you think about pink elephants.

So the trick is to set the rule [don't do X, do Y instead] and immediately stop thinking about X and move on to Y. Just shut down the "do X" thought and shift to Y. "Y" can be anything even the absurd like patting the top of your head 5 times because it breaks your subconscious programming. In fact, the absurd Y's seem to be more effective BECAUSE they a silly or ridiculous. Of course, as you gain skill at this method you can start using more productive Y's like doing 10 pushups or do a quick household chore, do a small task on your to-do list, etc. Once the subconscious program is broken then thoughts to do X will fade and you can move on to X2 that you want to change.