A kiss should be spontaneous and it would be a charm killer to ask, although I suppose it might work. But a kiss is normally the most romantic when approached in a mutual way. It’s nice when a man has the confidence to cup his hand gently on your cheek as he is looking into your eyes with a smile and leans in a bit to lightly kiss your lips. I doubt I would ever turn down a kiss like that, it’s sweet and shows a deeper caring and respect . Even if nothing came out of it, I would be forever flattered.
As caring and respectful as it may be, it’s not a thing for friends, or else there would be no issue, so it’s not something that people who are not in an exclusive romantic relationship with each other (or looking at it) should do. E.g. it’s not a proper way to thank someone for saving our life or to express appreciation, as a single-event devoid of any perspective of building up a relationship, so it shouldn’t be pursued by people who just want the kiss and nothing more. Moreover, while it’s certainly nice to have confidence, it’s not really very respectful to assume consent. A man who waits a while before kissing shows some respect, but a man who goes ahead assuming without a good reason that the lady won’t mind or at worst an honest mistake will have been made, should probably work on respect and reverence for a while. One just can’t accept lightly the risk of violating another person.
Ahh, asking isn’t necessarily a charm killer. Not if you do it the right way.
Yup. Doesn’t even have to be verbal.
Look into her eyes. Smile. Tell her how beautiful she is.
Sounds a bit like buying your way with a compliment. If I were a girl, telling me I were beautiful wouldn’t work here. As a guy, I wouldn’t really become more inclined to allow some more advanced form of contact as a reward for a compliment, either. Or perhaps you mean it as some indication that it’s more than just friends, since friends don’t normally tell each other they’re beautiful?
Twirl some of her hair in your finger. (This is a test to see if she pulls away, or if she is comfortable with direct contact. Touching someone’s hair isn’t as intimate as touching her face, for instance.) Tell her she’s eminently kissable. Smile.
Yeah. Or you could try with a hand on her should or taking her hand, something like that.
(If she’s already twirling her hair in her hand, it’s a pretty good bet your advances are welcome. Don’t know why, but that’s what we do when we like a guy.)
Same if a girl kisses your hand actually. Female friends don’t do that to male friends (okay, okay, I know people will come up with exceptions… let’s say they normally don’t

). Some “experts” claim it’s practically an open invitation to kissing.
By the way, correcting her hair (or wardrobe, for that matter) all the time typically means she’s attracted, somewhat nervous about the impression she makes on you, something like that.
There are of course more such signs, so just tell me if you want me to elaborate.
You’ve told her she’s kissable. She’ll either say “Well, then why don’t you?” Or she’ll say “Back off, Buckwheat!” Either way, you have your answer.
I’m a big help.
Yeah. To both, hehe. Another idea. You could circle her lips with a finger tip. Or just touch the corner. If she means it just friends, she will object, since friends don’t have a reason to do that. However, an actual kiss does not take place if she objects, just a lesser form of contact that she will most likely get over very soon and most probably won’t mind that much anyway. But of course, to do something like this, you would need some likely signs on her part. It can’t be a surprise thing.
Hint: You can try giving her red roses. Friends don’t normally give or take red roses (very special occasions, special friends, clear situations, excepted). If it’s a new girl and knows anything about flowers, she won’t accept or she will say something about being just friends or otherwise drop some hints you should back off a bit. If she takes them, it means that at least your interest isn’t repulsive to her. This is a good test because it involves no potentially unwanted body contact. If someone feels violated by being given red roses, that person obviously has a wrong definition of coercion.