Have you ever sat down and written these two different lists: 1. a list of things that you like about yourself (doesn't matter what, could be things you think you're good at, personality qualities, things about how you look). and 2. a list of things you're proud of (for example, on my own list I have "eating at a restaurant by myself" and "trying sushi". These were very big accomplishments for me!)
Write them down. As many as you can. Each time you look at it, try to think of a new one to add. You can stop at 25 if you wish

(to give you a goal!)
Look at the things you're proud of. Is there a theme? Mine have a lot to do with conquering things I was embarassed about - putting myself into situations around people where I would feel like I was standing out. When I need a new goal, I can think about similar things that might make me feel good as well (currently, I'm working up the guts to go to a spa or something. With a friend. Never been to one because I can't handle the idea of someone being focused on my body for any length of time! I'm also going to be staying at a hotel by myself for a few days... which is sorta scary for me. BUT my goal for that is to go and use the hottub.)
I find writing out a wish-list of things I'd like to do to be helpful.. it gives me things to work towards. If they're too big then I look at what I could do that might help me GET to that stage.
Anyway! I don't know if any of these would be useful, but they've definitely helped with my own self-esteem.