I don't know if this is right, but this is what I try to do in these cases.
First, I look at the behavior as a weakness. For this reason, I don't set my expectation too high. My goal is to modify the behavior to reduce the impact to the person's life.
Second, I treat it as a long term goal rather than a short term goal. With this, I expect it to be a long and gradual process involving a lot of extra work. The same is what I would do if it was trying to help someone with difficulty in math for instance.
I also do not push it too far. If I sense frustration on trying to moderate the behavior, then I back off for a while. I feel frustration is a sign it is not a good time to work on a weakness. After a bit of a break, I start working on it again. I worry if I push it too much, it may result in causing insecurity.
