Good question. My thoughts on what increases self-worth:

* Living up to your own values
* Managing yourself well - not too impulsive, not too inhibited
* Quality connections with other people (i.e., you are not socially isolated, you treat them well, and they are supportive and friendly)
* Encouraging feedback from other people (frequent criticism, rejection, being "micromanaged", or outright ostracism feels terrible for anyone and seems to be a major component in low self-worth)
* Being assertive (rather than passive, passive-aggressive, or aggressive)
* Having control over your life
* Learning and using skills that you intrinsically enjoy - that builds a sense of competency

I think that if we have gone through too many periods where we don't have enough of these things in place, it can leave a long term mark on us. I suspect that self-worth and self-confidence are somehow connected in ways I can't fully define (this is because I have tried working on one, and find to my surprise the other can also be affected).

A nasty problem is, when self-worth is low we tend to NOT do all the things necessary to increase self-worth. Same problem exists with self-confidence. I have no idea why this is so.