That's a very long way of saying I'm quite ashamed of myself. And now I'm very much into "if you love it, wear it." But along the way, I've made a few mistakes and learned a few tricks, so I'll share them.
* Wear only things you love *
This was one of my big project in 2007; editing down my wardrobe to get rid of clothes I don't really like but keep because you're "supposed" to have them. Example: khakis. I know they're classic, practical, etc, but I hate the way they look on me. I look like a pudgy soccer mom with fat thighs. So no khakis for me. (Of course, now I work for a corporation where I have to wear either khaki or black pants to work every day.)
One of the biggest mindsets I had to adjust was the whole "housecleaning clothes" idea. I used to have clothes for when I'm kicking around at home and going out the door meant at least 30 minutes spent finding an acceptable outfit and combing hair. Well, I pitched all my "work clothes" and now get dressed in the morning in an outfit I love. It's amazing how much more work you can get done when you feel pretty and socially presentable! (Side note: I'm still hard on my clothes when cleaning, etc, so now I have a lovely excuse to collect aprons. This is also great because I make sure there's always a pocket on my apron for my iPod.)
* Wear only things that fit *
Bras, pants, sweaters, dresses...they all look wrong when the don't fit correctly, and you spend the entire time adjusting. I know we all have that pair of skinny jeans we're working on fitting into, but here's a tip: just because you CAN get it on doesn't mean it should go out the door. And if you've lost a lot of weight, I know it's expensive to buy a whole new wardrobe, but that's why Forever21 was invented. Hit the clearance rack and pick up a few tees in your new size, rather than slopping around in something that will hold 17 of you. You confidence will show.
* Wear only things that work *
I'll be the first to admit that when we lived in Ohio I wore high-heeled boots 90% of the (snowy, icy) winter, and I still do most of my grocery shopping in heels. So I'm definitely NOT of the opinion that "ugly = practical." However, I make sure that I can move quickly in heels so I won't slow anyone down if I walk with them, and I doubt I'd be wearing stilettos if I was caring for three small children. Wearing clothes that are right for the situation are paramount to ensure you feel comfortable and confident. This does not mean that you have to look like everyone else, just that you can do what you need to in the outfit you're wearing. For example: when I'm photographing anything, I have to be able to move quickly and quietly, lie on the ground and get up again quickly, and carry a bunch of lenses. So that means flat shoes, (usually) pants, no wide or low necklines, and lots of pockets. I COULD lie flat on my stomach while wearing a ballet neck top, but I would be constantly concerned about flashing my clients, and that's not terribly professional, so I try to avoid it.
These three guidelines have made my life much simpler, so I'll stop here for now, and hopefully pick up tomorrow with ideas for carrying zest into every area of life.