What works is refrences to change your belief system. Like The Kidd was saying, the girls telling him he was good looking, intelligent, etc...those are refrences.
Think of a belief like a table top, and the legs of the table are the refrences that support that belief. So if you're walking down the street and a group of attractive girls whistles at you and says "Goddamn look at how hot he is", that's gonna be a leg (and a big one) of the table that supports the belief that you find yourself to be attractive...the more legs you have, er refrences, the stronger the belief is gonna be. If you have a six pack, that will be another refrence in your eyes that you're good looking, another leg to support the table top which will make the belief stronger.
Now what about shit you can't change that you have to accept? You're short, are bald, your name is Stew, whatever.
That's easy, just look at other successfull guys who are like that. Randy Couture is bald but has threesomes with models, you can just think "Fuck ya, I have the same hairstyle as Randy Couture!" You're short? Jean-Claude Van Damme and Sly Stallone are short guys and they clean up...or use too, till they got married. You can think, "Fuck ya, I'm the same height as Stallone and Van Damme!" See where I'm going with this?
I both agree and disagree. The thing is, your mentality (beliefs/self-esteem/confidence) creates your reality. So it'll definately help to work on your mindset. But you are right, references changes the beliefs too (but that not as effective), so it does go both ways. But the problem with references and trying to change them, is that:
a) You can get needy (looking for results/references/peoples opinions about you)
b) You doesnt really have much control over what feedback you get, even if you do improve yourself (fashion, fitness, etc). So the beliefs can both get better or worse
c) If your beliefs are founded on something external (woman complementing you etc.), they aren't really on a strong foundation. Once the womans complements are gone, your good beliefs are gone.
But you are right that action must follow, you can work on your mindset all you like (saying something like: I get approached all the time), but you still won't get approached if you sit at home all day. Action must follow!