Five minutes, usually 5 first minutes of interaction. So basically from the moment you notice each other. Looking away immediately when your eyes cross is not going to reflect good. (Seems your hiding something, like being a perv)
Then personality would almost never come into play for me. Usually I'm at a concert or something and I scan the crowd and notice what guys are there, but it's usually not until the middle of the concert or afterwards that someone comes up to me and starts talking. In Iceland it's kind of seen as a sign of desparation to hit on someone when sober. The nature of concerts changes dramatically as time goes on and people drink more. You could have Muck (death metal) play first and everyone would sit still listening, but if Sigur Rós played at 3 AM you could even have a mosh pit break out during some of their faster-paced songs ;)
It's not so much as making them look good physically. But good character lends to confidence and charisma and those are attractive to women. Women will take confidence and charisma over looks most of the time.
Lol, um... oh, never mind, if you haven't figured it out yet, I won't bother to mention it. ;)
And I disagree, it's almost as if they do look better. You notice their negatives less and their positives more. Just the very fact that the guy has the confidence to approach me and start talking, to me, makes him seem more attractive. That doesn't mean that I'm interested in anyone who approaches me, but it stresses the importance of confidence and boldness. Nothing more frustrating than a guy who comes up and starts chatting or dancing, and you get the impression that he likes you, but he just never makes any moves - it's like, geez, do I have to be the dominant one here? And it's not just that boldness in a guy is attractive in and of itself (although it is); there's also the subtle implication that, hey, this is probably the sort of guy who'd push me up against a wall and just... well, you get the picture. ;) Not everyone's into the same stuff, but at least for me, that sort of knowing-what-he-wants-and-not-being-afraid-to-go-for-it is really appealing - *within bounds*. If it crosses the line to where it seems like he won't take no for an answer, it rapidly goes from "attractive" to "scary". Heck, most "no"s in such a situation would in effect really be "not yet" anyway. *Always* listen for "no", spoken or implicit in her actions, and whatever you do, don't delay in responding to it. Trying to take another 5-10 seconds before backing off will seem like an eternity to her in which she goes from "concerned" to "totally freaked out". "Pro-tip": Don't freak the hell out of your partner!
An additional thing to mention: a major negative is if a guy seems drunk. Not just a little buzzed, but drunk. Drunks aren't cute. They can also be dangerous, especially in regards to the above. And there's even legal issues with sleeping with drunk people (drunks can't legally consent), although in practice that's usually only an issue the other way around. But it's still both illegal and immoral to sleep with someone, either gender, who's too drunk to realize (or later remember) what they're doing.