To overcome low self-esteem, change any bad attitudes and take responsibility for improving the quality of your life. Set boundaries and focus on things that are feel positive, but don't expect other people to provide your happiness. Indulge in personal passions to discover what feels good.
Negative thinking kills self-esteem, so work on redirecting defeating thoughts. When rehashing unpleasant events, try to be realistic and think about what evidence supports those ideas. Learning to examine personal strengths and weaknesses helps with this, and writing them down in a journal can help sort them out. Redirect destructive thinking by doing something positive such as helping others.
Practice being confident with choices and allow mistakes. Blaming others or wallowing in regret are bad for self-esteem. Worrying about the outcome or what others think only makes most people second guess themselves and feel unsure about decisions. Learn to say "no" and don't try to people please. Instead, think about how to improve on mistakes.
Spend time with supportive, loving people who bring out your strengths. Write down positive affirmations or quotes and post them around the house. Enjoy being alone by reserving time to meditate, read or enjoy nature. Many people have activities they once loved but stopped doing. Make a list of these things, and try to get back into them.