Honestly that's an interesting question to ask and I wish I could say everything without writing a novel. Obviously answers will change from person to person but personally I attribute "being content" with self worth if you can find that relatable.
What I mean is, Quality over Quantity. This is a good indicator if we're focusing on work self esteem. I used to push for the most numbers and when I spoke with people, I'd have a very robotic tone because I thought I was being efficient. Nowadays, I put more focus into quality work and putting more thought into my responses internally/externally. I am "purposefully" answering questions instead of responding with knee-jerk reactions.
It was really about taking a step back, asking myself "is this truly what makes me happy?" and coming up with ways I can go about it and grow. This definitely didn't happen overnight, it was a process that started in 2013 and I'm still "finding out" what makes me happy. I may or may not ever find the "true" answer but I feel like I'm personally heading in the right direction.