It would help to know what you mean by “judgmental.” Our society has fallen prey to moral relativity and any condemnation of an evil action is considered “judging.” Indeed, “judge lest ye be judged” is perhaps the most incorrectly quoted phrase.
We are free to judge the morality of an action. For example, abortion is an intrinsic evil and we are obligated to condemn it. Admonishing the sinner is a Spiritual Work of Mercy. By “judging,” we can actually have an impact on the salvation of other’s souls.
The problem of “judging” is when we judge the state of one’s soul. Saying that someone is going to hell, or that a recently deceased person is in heaven fit under this. If the culpability of a person is at question, we may be certain that sinful actions have been committed, but we may not be sure that they have committed mortal sin. Basically, we should not make judgments on something that only God knows.
For our society’s definition of “judgment” it is not necessary to correct our “judgmental attitudes.” However, in many cases I have found it prudent to tone down much of my “judging.” If we have no friends, then we are going to have a hard time saving their souls!
I would recommend trying to be open to talk to and don’t jump to conclusions. For me, I have found that my interrupting habits tend to correlate with my “judging.” By correcting my interrupting problem, I have become less “condemning.” If interrupting people is a problem you suffer from, I would recommending trying to control that.
The root of “judging others” is the sin of pride. Humility, the virtue that goes with pride, is perhaps the most difficult virtue to attain. If you catch yourself in a situation where you feel pride may get the best of you, perhaps you can lightly strike your chest and pray “Lord, grant me humility” or something like that. Perhaps say a prayer to your guardian angel or the Prayer to Saint Michael when you find yourself in a tough situation.
Good luck. You are in my prayers.