I've used these ideas with the students on my Confidence Building courses - I've seen the benefits and hope that you will too;
Learn how to do something well. Being good at something boosts your confidence and is fun.
Realise being shy is OK. Half of us are extroverts and half introverts. There are advantages to both so be proud to be as you are.
Beauty does not bring happiness. Happiness and confidence do bring attractiveness. Learn how to make the most of your good points and enjoy them.
Set realistic standards for yourself. Perfectionism undermines your pleasure in your achievements. Too low standards give little sense of achievement.
Deal with your problems. Unresolved issues undermine your confidence. Decide what needs to be done, do it and move on.
Do not criticise yourself. Over time, the bad things you say about yourself make you feel bad. Replace negative sayings with positive or neutral ones.
Recognise that what you want is as important as what others want. Ask for what you want and compromise gracefully if necessary.
Asking for, and accepting, help is a normal adult behaviour. It shows strength, not weakness.
The quality of your relationships has a profound affect on your self esteem. Avoid people who put your down or complain a lot. Find new upbeat companions who are enjoying their lives as their attitude will rub off on you.
Smile and stand tall. Behave the way you want to feel. Your facial expression and body posture do affect your emotions.