How to bust rationalizations
Have you ever think about rationalizations and why they are effective. I think that our rationalizations work because we use them in moment when we desperately need something to believe to.
When you think about your rationalization later, most of the time you know how your rationalization is stupid. It’s almost like when you think about some conversation an you said to yourself: “Why I didn’t tell…?”
To bust my rationalization I use something that I called “Al Bundy principle”. If you look “Married with children” TV series you know that Al is not brightest guy in the world, but he always has something sarcastic and funny to say. Why?
OK it’s a fictional character 
but other part of answer is that he always has something funny to say because his scripts are written in advance.
You and I, and everybody else, we are all creature of habits. You know what you must (want, wish) to do, and you know what are your favorite rationalizations. Use your knowledge think about your favorite (even better write it) then think (write) few rationalizations buster. Then when you start to rationalize you will for every rationalizations associate few rationalization busters, and because you desperately want something to believe to and dominant thoughts in your head are positive you will do positive stuff.
There is German “Übung macht den Meister” or in English practice make perfect. Even if you don’t succeeded from first with repetition you will make new neuron paths in your brain and associate negative rationalizations with positive thoughts and became happy creature of action instead sad creature of rationalizations.