While we're on this subject: my "pimp juice" is my professionalism (no joke

). As a pilot, I've learned that passengers do not judge your skill as a pilot based solely on the way you handle your aircraft. A huge part of this is how you conduct yourself in the cockpit. If you goof off and act silly, even when flying people you know well, they will not respect you as much as a pilot.
The same goes for real-life scenarios. Think about how people react to someone who has an air of competence and control, versus someone who acts stupid and looks sloppy. Personally, the way I'm able to be confident in social situations is that I go out of my way to be that guy who gives off a professional and competent attitude. Now, think a moment at how many people you see who really act this way? There are relatively few, especially in the age group most people at this board belong to. Having a professional attitude sets you apart from other people, in a good way.
To summarize, here's how I've found to be a great way to gain respect and confidence: Be a gentleman wherever you go (this may sound "old fashioned," but you'd be very surprised to how far you can go if you just show a little of this), dress presentably, keep good posture, maintain eye contact while talking to a person, stay well groomed (personally, I find it hard to take a person seriously when they haven't had a haircut in 6 months, and have some sort of fro goin), and finally, you need to know how to make a good first impression with a person, in order for this whole "professional aura" thing to work. It's a proven fact that in the first 10 seconds (count em') after meeting a person, you have ideas of what this person is about set in stone in your own mind. As unfair as it might seem, if you walk up to a girl and the first word out of your mouth comes out stuttery, she may think you as insecure. Conversely, if you walk up to that same girl, look her in her eyes, talk to her like you respect her (and you should do more than
act like you respect her, in my opinion), and do this confidently, her view of you from then on will be a good one.
I could go on and on about this; into body language, and the like, but I think that's a little redundant to what I just said. Most of this is common sense, anyway. This system has helped me be more confident, and have more people respect me in the process.
Quick Edit: When I say dress presentably, I don't mean suit and tie, by any means. I agree with what SR said: dress well for your style. Personally, my style is button-down and polo shirts, and the like.