>>25529A big part that helps is doing things you can be proud of. Hobbies, skills, things you're an expert on, places you've been, etc. Things that you enjoy and can do without needing a girl with you. Finding something you're good at/getting good at something makes it a lot easier to think higher of yourself. It makes you feel more valuable and useful.
My things are drawing, music, and language. I still kinda suck at most of it, but I'm working hard to improve every day…