C'mon, man, that's nothing two good drinks won't do for ya!
-Joking-
I have no idea how to get in that mindset permanently, but I've been taking notes of the little things that elevate me to that mindset and trying to stack as many of them back to back as possible.
A big influence on my mindset is the expectation that I have for it, so when I believe I should be happy I usually am - so I've been trying to re-wire myself to think that I should be happy a lot more.
One of the most important things that helps is to get good sleep and get out of bed quick instead of lingering. Usually how I woke up ends up being a metaphor for the entire day, so I hop out of bed and get going as fast as posssible to avoid the trap that is laziness.
Another is doing something physical that I enjoy. At one time it was snowboarding, but with that not available I've been struggling to find something. In spite of the fact that I have nothing right now, I remember a time when one good run meant that I could get hit be a semi truck hauling manure and have good humor about it.
Other than that, mini-victories achieved by setting small but productive goals and meeting them each make a slight improvement to my mood. Even though I didn't have to work today, I got up and got the dishes out of the sink, learned a new trick on my guitar, had my neighbor offer me a job at a bar he runs as a bartender, and I read something that was just hilarious on the internet. Each little thing adds up to a good day, and to top it off I think I'll head out to the mall and get a phone number or two.
Come to think of it, how you get up doesn't matter too much, considering I woke up with a screaming headache hating the world. I got up anyway though, even if it was just to get a bottle of Tylenol from Wal-Mart it was nice to get out of the house. I'd be much less happy if I had stayed in bed longer than necessary.
There are some more difficult things that improve my overall mood in the long run, the most important of which is learning how to best exhibit my strengths. Since I know that my story telling has evolved from me rambling to something that people actually seek me out for, I know that I have something to offer a stranger I might approach. I know I can make her laugh, and that makes me feel like I deserve her attention and would be doing her a favor to show her this. Nothing kills approach anxiety like having a good reason to believe the girl would actually like to talk to you.
Also paramount to my positive attitude is a belief that I'm making the most of myself, going to school to get a degree (and an education too, if I'm lucky) in something that I enjoy and stands to make me some serious dough, as well as researching how to been wealth and better relate to people. My ambition tends to set me apart from the common man, and I'm left with yet another reason to believe that any girl would be lucky to have me.
Confidence tends to be an upwards trend, as good displays of it tend to reap positive results which in turn raise your confidence - not unlike when you think you might not know what to do, but your forced to try and succeed, you're encouraged to try again even if you fail the next 5 times in a row because you've already demonstrated that it can be done. This is true about picking up girls, but can be applied to anything.
And, repeatedly failing helps too. I could never be so self assured if I didn't have times when I've been at the bottom of the gutter and worked my way out to think back to as motivation that I can do it again if I must, and just as long as I remember how I got so low to begin with I know I probably wont end up like that again. It's always important to learn from your mistakes, because there is no confidence killer greater than repeated failure resulting from your own actions when you knew better. It's easy to doubt your worth when you know you are responsible for the torture your going through because you simply failed to try avoiding it.
Strong confidence isn't easily built, but if you do it right through genuine improvements it becomes bulletproof, and these 'techniques' you read about really do become second nature. It's easy to feel valuable when you really are.