For me (rather unhappy childhood, self esteem better now than it was then but it doesn't come naturally) I've found the concept works better looking at my kids than myself. For me they are this perfect pair of people, and what they say and do is dear to me because they are them, and I am their mum, and that's how it works. They don't need to impress me, don't need to set the world on fire - they need only to exist and be themselves fotr me to be properly proud of what I did in bringing them into being.
I hope they can have the same feeling for themselves - it's a feeling of not needing to earn your place in the world, of simply deserving it because you exist.
You also asked "Those who are reporting good self esteem - how do you reconcile when people are unkind/point out character flaws in you? Doesn't it shake your core belief in your self?"
It used to is the short answer, but I learned that in between experiencing this and reacting to it, you can insert a conscious thought. Why is this person criticising me? Are they being a friend, do they have my best interests at heart? If they're not being my friend by criticising, I'm upset a little that someone is being nasty to me but I can shake it off fairly quickly. What is actually harder for me sometimes is if someone is giving genuine well meant criticism that hits the spot - I find it hard to admit if there is something I should be changing.
My experience, I think because of my very early childhood, is that it's not easy or maybe even possible to change the sort of gut emotional responses. But I have found it possible to sit back from my emotions and question what's going on. With awful people who I have to get along with, I have a thing: I just say to myself "OK I'm going to imagine that scowl on your face is just what your face does, it's nothing to do with me" and carry on regardless.