It's one step forward, two steps back. I went through some "stuff" where it was imperative I learn some new behaviors. Thinking about it is not enough. What tools have you given yourself?

Sometimes, just choosing to not say anything at all is a really good first step. Practicing saying "uh huh" or "I see" instead of offering your opinion.

Use the Serenity Prayer:

God ( or whomever/whaterver you pray to)
Grant me the serenity to accept the things I cannot change,
the courage to change the things I can,
and the wisdom to know the difference.

Break things off into sizable goals. An example might be, "just for this one day I will not make snarky comments about my mother in law/co worker/husband/job/kids etc". Don't worry about what you are going to do about it tomorrow, just worry about doing one thing different for one day only. I forget what the number is on how many times you have to do a new behavior before it becomes habit.

It's not in your genes, it's learned behavior in your family patterns. Therefore, you can unlearn it.
Practice saying, "no".
Give people the dignity of running their own lives, making their own mistakes and learning to be accountable for them.

Think to yourself, "what is the worst thing that will happen if I do not interfere, comment, try to run a situation..." Usually it's not that bad - see the above about giving people the dignity of running their own lives.

Remember, there's only one God and you aren't it.