In psychology, self-esteem reflects a person's overall evaluation or appraisal of his or her own worth. Self-esteem is an opinion not a fact.
The way we view and feel about ourselves has a profound effect on how we live our lives. These opinions are shaped by experiences in the family, at school, from friendships and in wider society. Self-esteem involves our ability to think, to deal with life and to be happy.
In Latin, esteem actually means 'to estimate', so self-esteem is often defined as how you estimate yourself. To do that, you need to ask yourself certain questions.
People with low self-esteem find it hard to answer yes to these questions.
Many people assume self-esteem is the same as self-confidence and although self-confidence is related, it's not the same. Self-confident people may also experience low self-esteem, for example, actors, celebrities and public figures that appear to be totally self-confident may have poor self-esteem off stage or away from the media attention. Think of the late Princess of Wales or Marilyn Monroe and you'll see that public adulation is no guarantee of self-belief.
Most people experience low self esteem at some point in their life (e.g. if they lose their job or relationship) but they can also experience high self esteem at other points in their life (e.g. if they are promoted, successfully complete a challenge or fall in love). However, those who can't bounce back after their self esteem has been bruised, and constantly feel negatively about themselves, may find counselling beneficial.
Rejection or loss at any age is likely to undermine self-esteem. Events like a partner being unfaithful, being ostracised by friends or bullied by peers, dealing with an unsuccessful job application, having an accident, a burglary, or coping with a death are likely to provoke feelings of loss and threat. For some this is temporary, while for others the effects are long-lasting.
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 have a basic human need to be wanted, noticed, and included. We want to contribute, to be of value, and make a difference - in other words to matter.
Our self-esteem will continually fluctuate and is affected by events and encounters with other people. We are also constantly judging and evaluating ourselves, often in comparison with others. Observing ourselves in relation to other people can be a helpful source of learning and feedback. Yet all too often comparison slips into competition and others become a yardstick by which we evaluate ourselves 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 our behaviour and appearance we may seek to change or develop, but a sense of self is also based on self-awareness and self-acceptance.

Change means stepping into the unknown and taking a risk. Remember that small changes add up. Call on other people to help you by being encouraging, taking an interest, giving feedback, and making suggestions.
Do things for pleasure, for fun
Look after yourself physically
Use rewards, but avoid punishments
Cultivate good relationships - with yourself and others