There could be many reasons why you feel that your self-esteem is low. Usually the answers will come from you as to why that is the case. Some examples of low self-esteem include not being appreciated by those you want to appreciate you; not having certain skills you would like to have; dissatisfaction with your relationships; dissatisfaction with your financial situation, or job potential, etc. You get the idea. You will have to ask yourself the specific questions as to what is missing in your life right now, or what is in your life that you'd rather not have. Basically, to be confident and have excellent self-esteem, you need balance between several very important components in your life. These components are health, family, friends, career, spiritual, and financial. Many of my self-confidence clients confuse career with financial. It is not the same thing. For example, you may have chosen a career that you love with a job that doesn't necessarily pay great, but you just love your job and are happy with it. On the financial side, you may have learned to manage your money in such a way that you are able to keep enough on a monthly basis to invest wisely and make it grow exponentially. Does this make sense?
So if you examine the components of your life and just make a brief analysis for yourself, find which aspect needs the most work and simply make a plan. Since each human being is a work in progress, each and everyone of us has something to improve on in every aspect of life. The trick is to be honest with yourself and just take into account what is already going well and what needs some work. Then learn about ways to polish what needs polishing. Meet likeminded people, take a class, hire a coach, read some practical literature in that area. Are you working too hard and feel you need some cool hobby? You know the answers already. All you need to do is ask yourself the right questions. Then take action.