I have always had low self-esteem, though I cannot even pretend that I have had to endure what many of you in this thread have had to endure.
My late dad had a dominating personality, and he emotionally abused me. I grew up believing that I was a complete failure and a total loser. My feelings and thoughts were never treated as being valid, and I was never allowed to disagree with my dad. My mom would often tell me that I needed to see a psychiatrist.
Only in recent years have I begun to realize that other people make the same mistakes that I do, and have the same problems that I have (i.e., that I'm normal, and not some complete loser freak). This was a revelation when I first discovered it.
Several years ago, I attended a Personality Seminar, where I learned that I was the way I am because that was how God made me, and my melancholy personality was actually given to me by God purposefully, and along with it came a positive side (because it was a gift) and a negative side (because everything in this world is tainted by sin). This was another mind-blowing revelation to me: that God could actually use my personality type, and it was not just a curse that I needed to have fixed.
Unfortunately, this new-found revelation was so incredibly mind-blowing to me, that I made the mistake of stopping by my parent's house and sharing my incredible news with them. Well, my dad told me that I was completely wrong, and in 15 minutes, he had completely destroyed everything I had just learned. I went back to feeling like a complete failure in life.
However, more recently, I read a little book by Andrew Wommack called "Low Self-Esteem: The Root of all Grief." In it, he said something that was another shocker to me: that low-self esteem is actually pride. He said the answer to low self-esteem is dying to self. If you truly die to self, then you won't think about yourself anymore. You can kick a dead corpse around all you want, and it won't feel a thing. A dead corpse doesn't worry about its problems. A dead corpse doesn't get depressed. In the brief way that I'm explaining it here, it may not sound very convincing, and it would probably make a lot more sense if you read the book, where it explains it in much more detail. However, here is a similar article that explains it in summary form:
http://www.awmi.net/extra/article/root_grief