Difference between trying too hard and making an effort

I've been musing on this for a while, (perhaps prompted by the regular and frequent pictures of Taylor Momsen that I keep running into on the interweb)... What's the difference between trying too hard and making an effort?
Taylor Momsen keeps cropping up in this thought process because when I see pictures of her dressed in underwear, stockings and stripper heels during the day, whilst peering out through dark, dark eye make up between her bottle blonde extensions, I can't help but think "ooh she's trying a bit too hard isn't she?"
I feel bad about thinking this because I vaguely remember what it's like to be 16 and desperate to be different and rebellious. Like all 16 year olds, there are rigid categories of people separated into "cool" and "not cool." She will be on the cool side and the majority of the rest of the world is in the not cool category. If you don't get it, you're not cool. So anyone who thinks maybe she should wear more clothes or less make up, is by definition not cool. But this ignores the very non-cool factor of trying too hard.
To a certain extent, Ke$ha is coming from the same direction. She is so desperate to be different and out-there, but the very act of trying so hard virtually guarantees that the look or style will not work. I can almost see her thought process in an outfit..."a bit of David Bowie-esque slept-in make up, some bed head hair...I'll look like I've been out partying all night...add in necklaces and bracelets to add to the modern hippy look..done."
And despite the fawning over her originality and sheer dedication to fashion at all times, I feel like Lady Gaga tries ridiculously hard too. It's like "we get it, you're a dedicated follower of fashion, you must suffer for your art, blah blah blah."
Now, certain people look like they've made an effort without trying too hard. I would put Dita Von Teese on that list, she's always immaculate but in her own vintage style. There's no attempt to shock or attention seek, she simply dresses well in a thoughtful and considered fashion.

Anyway, this has been a long and meandering post but the subject's been on my mind recently.
Rx