(25M) How to get my GF (23) self-conscious/confident about her body?

First post, so Hi to everyone.

My GF (together about 1.5 years) had a rough life because of her mother and situation at home (her father added his own 0.02 to this, but not that much). Her mother is despotic at home to her children, her problems at work affect the atmosphere at home. She won't listen to her daughter sometimes and tells her that she didn't listen. Mother dominated her life through taking offence whenever she wanted something else. Even clothes shopping has to be approved by mother when they are together. My GF tries to reduce this sometimes, goes on her own shopping etc. but I think it's not enough and it'll take forever to liberate. I've even made her go to specialist and she meets psychologist once a week.

The problem is that she won't move out (psychologist told her to stay; don't know if he knows what I know), she doesn't accept any compliments (as she speak) or gifts (saying she's not worth that; even small things). When doing new things she's sometimes impatient, too much critical about her work. She does not accept her mind or body, sometimes focus on mental punishing herself ("I don't have anything good in me"; that kind of stuff), she cut herself few times but stopped some time ago.

The good things are:

• she reads a lot of books (not to learn, but she does something and book type can change),
• she's working in some kind of services (which means she meets new people; she's afraid of new people),
• she studies at weekend (ambitions, good),
• she loves sex :) (which I think is the good way to start making her self-confident),
• she tries to lose weight, sometimes exercises, tries to keep calories (another good start).

Well, I would like to tell you that what I wrote is all, but there is a lot of stuff that I don't even know where to start with. I will answer any question or advice as good as I can, just don't have any idea how to write all the things right here.

How to make her more self-conscious/confident?

tl;dr My GF is very shy, not self-confident and has some bad habits made to her by her mother. Through accepting her body and some pushing on her boundaries in sex I would like to make her more self-confident and accepting.