So many things in life hinge on preparation. An extra minute of thought can make a bigger difference than you'd imagine. We've heard the sayings "put your best foot forward" and "allow yourself to succeed" for years, but far too often we don't put those maxims into practice. It's not about trying your hardest or being dedicated, etc., but more about doing the little things to accentuate your strengths and suppress your weaknesses.
I admit that this post was spurred partially by the famous "gym, tanning, laundry" clip from Jersey Shore. Like him or not, Mike "The Situation" has a point there. If you want to feel at your best, then take the necessary actions to reach that point. If your confidence will be high because you feel pumped and fresh, then so be it. Do what you gotta do.
You can take so many measures to optimize your appearance that it bothers me to see people out in public that look like total shit. Your hair doesn't look good when it gets long? Get it cut on a regular basis. You're a few pounds overweight? Don't wear horizontal stripes (and get off the couch, but we'll try to stay on topic). You're below average height? Don't wear excessively baggy pants, they make you look shorter. You're very fair skinned, even in summer? Avoid too many dark colors that make you look even whiter. Finally, keep in mind that while image isn't everything, it's quite often the only thing. Like it or not, we all make unconscious snap judgments about other people based on how they appear to us, no matter the setting. So it never hurts to spend that extra minute in front of the mirror before leaving home.
It's not limited to appearance. If you're habitually late, set all your clocks and watches 5 minutes ahead. If you know tomorrow is going to be a very busy day at work, get there a half hour earlier than usual. If you don't like to dance or simply suck at it (my hand is raised), then don't try to meet girls on the dance floor of a bar or club.
It's simple. Figure out what you're good at and stick to it. Fortune favors the bold, but it also favors the smart.