I went from avoiding women altogether because I thought I was too ugly to attract anything above a 4 to being more outgoing and genuinely not caring what women think of me. Here's how I did it:
I was always decent looking, but I made slight adjustments (shorter hair, better clothes...not for women, but so I'd feel better about me.) Also, dating a girl that was easily an 8-9 and looks like Renee from 24 helped prove to me "I can attract a hot woman with my looks."
After that I just stopped giving a ****. I have a global view "I'm not really hot, but I'm not ugly either. I'm in the middle and if I want it, I have to work for it, but I at least have a chance." If a girl rejects me, I just accept that she wasn't interested in me or not interested in getting hit on at the moment.
Luckily, I haven't had any of those horrible rejections that people talk about, where the girl says "Go away creep" or "I'd never go out with someone like you." I can imagine where that'd sting. But honestly, what's so bad about hearing "No, sorry" or "I have a boyfriend"?