From a gal's perspective, it sounds REALLY shallow but when I needed a self confidence boost to feel better about myself, I got a new hair cut and colour, got my nails done, did a little bit of exercise, got a mild tan (sunbed or bottle - your choice!!) and bought a few new clothes and shoes.
Nothing extravagent (alas, I'm not made of money) and it sounds extremely transparent but feeling more healthy and attractive made me feel much better about myself; it wasn't about attracting men because I was (and am) already in a relationship but I just felt a little happier and healthier.
As to the mind set, I think feeling good about yourself physically helps with that. Don't know what kind of job you have but maybe you might want to consider stretching yourself in that way; either taking on additional responsibility (if that's possible), looking for a new role (if you fancy a change) or taking on a course to help develop some new skills.
Maybe try a new hobby or interest. I tried windsurfing and it was great fun. Got me out of the house and I met some new people. I also felt more busy which was nice (as i was in a bit of a lull).
Ooh just reminding myself of it is making me smile. Think I might go get my nails done again this weekend!!
Sorry - if you're a boy, I don't have a clue what to say!!!!!