My mother used to (well, probably still does, but it's no longer my problem) very openly gawk at people with unusual piercings or hairstyles or modes of dress. When I'd get embarrassed by this, she'd tell me, "But they want attention, or they wouldn't do things like that! They want to be looked at!"
I hear the echoes of that sentiment when people complain about a woman dressing all sexy and putting on makeup, then being offended when guys hit on her.
Because maybe she does want attention, but not from everyone who sees her. Maybe that attention was supposed to be in the form of admiring looks, but not hitting-on; maybe it was supposed to be hitting-on, but not groping. Or maybe she wants to be hit on, but not in a creepy way by creepy dudes.
Or maybe she doesn't want attention at all. Maybe she just wants to look nice to feel good about herself, in a way that isn't entirely sexual. Looking "good" and looking "sexy" have a lot of overlap for women, and an outfit that to her says "I'm going to look casual but fashionable, I take pride in my appearance" almost always ends up showing a bit of skin.
Women also face a catch-22 that the pierced people don't--we have to look sexy in a certain degree just to not be ugly. Going out in baggy jeans and a sweatshirt doesn't protect you--it gets you shit for not showing it off and being a presumed lesbian man-hater.
With all this ambiguity, what's a dude who's not psychic to do? Don't be creepy. Don't assume that because a woman is in a short skirt and heels that she's any more up for it than a woman in baggy jeans and a sweatshirt. Don't think that the way a woman is dressed gives you permission to do anything you wouldn't otherwise.
So what's a dude who's not psychic and not celibate to do? Don't be creepy. Very few women are horrified and offended by being politely hit on. When women complain about getting too much attention, usually that attention came not in the form of "hello, pardon me but you're very beautiful, would you like to get a drink sometime" but in catcalls, staring, leering, refusals to take a hint, refusals to take a not-just-a-hint, and inappropriate touching. That shit's not ever okay.
In general, women who complain about male attention when they were asking for it, got shit that was a lot worse than just "attention" and they weren't asking for it.
Side note: Guys, when you hit on a woman and she says "no," do not ask "why not?" I've heard this quite a few times and it absolutely flabbergasts me. Because no, is why not. Because I don't owe you anything, including an explanation. Because the odds of me going "oh, you're right, there is no good reason, silly me, let's fuck now" are infinitesimal. Besides, the explanation is usually very unflattering to you, and you don't really want to force me to say it.
Ugh. I write these posts and I always worry it sounds like I don't want guys to hit on me. But I do! I'm very attracted to guys! I love being nicely hit on! I just don't want to be hit on by guys who can't tell the difference between "expressing attraction to" and "creepily creeping on like a creeper."