What I've been saying for the longest time and have had very, VERY good results is:
"Pardon me, I believe you are the most beautiful woman I've noticed today." (beat. and turn to walk away then immediately turn back) "On second thought, Make that the third most beautiful woman I've seen today. I took my -(Mom, Grandma, Favorite Aunt, Landlady or whomever) - out for a wonderful (Breakfast, lunch or dinner)."
Not only does this have a drastic effect on her on totally different levels and make you seem like a big hearted sweety, But also let's her know off the bat she won't be the #1 woman in your life and you could live another day without her.
I've had women pay for my meal and then buy me drinks because I had the sac to say that to them and not bat an eye.
Karma