Everyone has insecurities but i found that it was easiest for me to build self confidence by surrounding myself with real friends who don't put me down and doing something i loved for me it was a combination of swimming and performing find a sport or club that your passionate about and make sure your "friends" are treating you rite Hope this helped :D
go in the mirror and compliment yourself, wear stuff that makes you feel good about yourself and that is yourself,join a sport or try something you always wanted to do and accomplish it,do stuff for your life on your own like go after your dreams and maybe doing stuff and accomplishing things on your own will give you self confidence or take risk or change the stuff that lower your confidence to boost up your confidence
Try new things and experiences, especially ones that you are scared to try.
Write a list down of 30 good qualities that you have. Keep this list handy to look at when you feel down.
Go after the things you want, and don't be afraid to say NO to things that conflict with your values. Set boundaries for yourself.
Focus on your own happiness in relationships with other people, and put your own needs first.
Find the cause of your self-confidence issues, and seek counseling if you are not improving. Did you suffer neglect from your parents, or abuse when you were a child? It's important to face these issues head on.
“You gain strength, courage and confidence by every experience in which you really stop to look fear in the face. You are able to say to yourself, 'I have lived through this horror. I can take the next thing that comes along.' You must do the thing you think you cannot do.” -Eleanor Roosevelt
You wouldn't worry so much about what others think of you if you realized how seldom they do.” -Eleanor Roosevelt
“I do not care so much what I am to others as I care what I am to myself.” - Michel de Montaigne....... So you get the point live as if today was your last and don't care about what others think.... Stay true to yourself...
There are a whole ton of ways 1 first of all realize that you are worthy of loving yourself
2 do something that is nice for someone else. It will make them see how great you are, and it will make them like you more, which will give you more self esteem knowing that you did something nice for them and they will appreciate you.
3 get a wardrobe that makes you feel good about yourself and one that expresses yourself. However, they don't have to be the most revealing clothes ever. If they are very revealing, then you won't feel very happy knowing that guys only like you because they see more of you, not for who you are and how great you are, and that will just get your self esteem really low.
those are just a few ways.
If you need any more tips, just google it. You can probably find a lot of stuff in teen magazines and stuff
Accept your appearance and flaws. Take care of yourself and keep yourself in shape. Always be proud of yourself and always make yourself look your very best. Do not try to look good for no one else but yourself. :)