Any guy can be charming. It really just boils down to a few well-placed compliments, usually relating to how beautiful your woman is.

This isn't really advice for how to "score her", it's more like "now that you've scored her, remember to continue to do this". So you don't really mean "any guy can be charming", you mean "any guy who already has a girlfriend can be charming to her".

Because quite honestly, saying that a woman is the most attractive female in the room is something that is only guaranteed to go over well if you are already involved with that woman. If a man says to a woman that he doesn't know "You're the most beautiful woman in the room", the chances of this line working magic are directly correlated to how attractive the woman already finds the man. If some scummy guy says it, it's skeevy. If some cute guy says it, it's charming. If some guy is charming, it's because he's attractive in some way, and he won't be able to teach you anything unless you're attractive too.

Married though I am now,years ago I found the most effective ice breaker in bars and clubs was 'hello, how are you?' Works because the woman is not treated just like a potential score and is not forced to make any decision - (should I dance with this guy? Let him buy me a drink? etc). She can simply return the greeting and stay or walk away.

Also, if a guy wants to dance with a girl, approach her at the bar or her table BEFORE and say "I really like the way you dance, will you dance with me later when a better song comes on?". Much better than being shot down in flames in the middle of the dance floor. Never got turned down, neither.