Here's what I've learned from practicing living with disapproval:
For starters, disapproval from someone is a great time to self-examine to see what truth there is in what they think. There's always some truth, and since I got good at self examination, I find the truth very useful for self improvement. I define being good at self-examination as being able to see myself as I am without pain from seeing my imperfections. I am very imperfect. I've gotten used to that fact. Sometimes it's embarrassing, but usually not painful. I can use the energy I would have used to kick myself to make needed changes in myself.
Then, living with disapproval also motivates me to do a daily inventory on how I've treated other people. Sometimes it takes a bunch of days for me to get to my real motives for what I do, but I tend to grow in respect for other people as I work on this. Slowly; sometimes quickly, I get my side of the street clean with the person who's disapproving of me by treating him/her with respect. This REALLY helps me not take their disapproval personally. As my dear husband used to say, "If I call you a whore, does that make you one?" (His sommaries of spiritual truths tended to be fairly colorful.)
Eventually, usually after some considerable time and effort on my part, I begin to gain some compassion for the other person. There's almost a 100% chance that they are judging me because they are afraid of me in some way. About all I can do about that is to be as harmless as I possibly can and continue to treat them with respect.
Through all this I get happier and more peaceful. Which, by the way, can drive the disapproving person nuts.