For example : you may feel low in school in front of your class mates the reason could be that you think you are not good looking, you feel shy to put forward your views etc. The reason could be anything but you have to think about solutions to the problem. Ignoring the problem is not going to help you.
You should accept yourself the way you are. Every person is different and no one is perfect in this world.
One mistake people do is try compare their negative points with others positive points. For example: Tom is not good looking and a thought keeps on creeping into his mind that 'why do I look like this and all my friends are good looking why am I not like them'. You should compare your positive points with others positive points and see who is better. This will be a fair comparison.
Always remember people look at you the way you look at yourself.
You should recognize you strengths and feel proud. Regularly do things that you are good at . If you are good at painting then come up with something creative. It will boost your confidence.
Always set goals for yourself and try to achieve them. Do not commit to something that you know you cannot achieve. Success is the best esteem booster
When something goes wrong instead of thinking what went wrong try to think about what went right. Take out the positives.
Taking calculated risk can be a win-win situation as it boosts your self esteem.
Sit back, reflect and analyze your acts. Think of your life as a Hollywood movie and you are watching that movie, you will get a good idea where you are going wrong and where you have to improve.
Don't hesitate to visit a counsellor to help you boost your self esteem.