Very good answer, Modesto! The key to self-esteem is self-valuation. You must look inside yourself to determine those things about you that you consider valuable. This ideal goes hand in hand with your views on society, spirituality, your environment, etc.
We each have something valuable to offer--and we need to understand how important that is. We need to get in touch with and appreciate our uniqueness--outside of what others may think of us. It is only then that we can determine what we want out of life and what we should come to expect from others. We do devalue ourselves by accepting less than we are worth. But we must first determine our self-worth before we can demand anything from others.
Knowing the definition of self-esteem is the easy part. Achieving a high level of self-esteem is a journey in and of itself.