What we feel about ourselves is not based solely on what we do. It usually involves our relationships with others, and whether we feel worthwhile as people. We all have a basic human need to be wanted, noticed and feel included; we want to contribute, to be of value and to make a difference - in other words to matter.
Self esteem continually fluctuates, and is affected by events and encounters with other people. We are all constantly judging and evaluating ourselves, often in comparison with others. Observing yourself in relation to other people can be a helpful source of learning, yet all too often comparison slips into competition, and others become a yardstick by which you evaluate yourself as good or bad, competent or inadequate.
The reality is we are all different. Each of us has strengths and limitations which we need to learn about, and learn to live with. There are aspects of your behaviour and appearance that you may seek to change or develop, but a sense of self is also based on self-awareness and self-acceptance.
Change is not easy. It means stepping into the unknown and taking a risk. Inevitably this means that some initiatives will work well while others don't work out as you hoped. You can help yourself by being realistic in your choices and seeing each success as a step in the right direction. Remember that small changes add up.
If you find it hard to know where to start in making these small changes, maybe talking it through with someone who can look objectively at your situation, and who can help you find your own path to confidence is what you need. If this is you please contact me.