The way most people say to help boost self esteem (that I've noticed) is tell yourself something positive over and over again until you believe it. Avoid saying anything negative about yourself like "I'm ugly" or "I'm not good enough" etc. (not saying you say those things, just examples.) Another thing to do is to accomplish something small that has been making you feel as if you couldn't do something, it can help with the self-esteem field as well.

I used to have extremely low self-esteem and one day I just said "Ya know what? I think I'm awesome." and I told myself that enough times, that I started to believe it, and then I started to realize that all the negative things that were holding me back were because I didn't like me, so I assumed no one else could like me. It's funny how they say "No one can love you until you love yourself." and that's true to a point, it should read "You don't realize anyone loves you until you love yourself." at least for me.