Again, we cannot stress enough the importance of having good observation skills. While the line above is one example of this particular technique, you can use this second one as well or some other variations of it. What we are saying is, use a line that states something about her, basing on what you have observed. Single her out. Make her feel that she is not like the others.
Say, a beautiful woman is hanging out at the bar and talking to her girlfriends. Pretty sure, she had received countless propositions from men throughout the night. The truth is, this can be very annoying. Yes, gentlemen, being hit on can get old real quick, especially if these come-ons aren't welcome.
However, all hope is not lost. Just because your fellow brother-in-arms did not succeed in wooing the lady, it doesn't mean that you should also crash and burn. Offer something nobody has: make it all about her and not your desire to win her over.
You can do this by commenting on something about her that would only increase her interest in you. Rather than immediately shut you down, she would ask you how you've come about that particular observation. Take this conversation as an example:
"Hey, you are not from here, are you?"
"Hmm, what makes you say that?"
"Well, for starters, you are the only one smiling here in this bar."
This could be a great way of sparking a conversation with her which would ultimately lead to introductions and mayhaps, exchanging of numbers. Bottom line is, see her as a person and not as a trophy to be won over. Then, she might see you as someone interesting to talk to and not just one of those pesky guys who have had hit on her and her friends way too many times.