I have had repeated success with the dingley-dangley earring variation of the 'same dress' line.
As a matter of fact targeting gals who wear dingle-dangle stuff ups your odds. Couple it with "women who wear dingley-dangley earrings are the best flirts" and you have a ggod start. I'd say 7-8 out of 10 will give you some sort of a flirty behavior off that line. Once she does she's engaged in the conversation and all you have to do is follow her cues. A very subtle shift from you trying to please her to curry favor and gain her attention to her trying to please you by proving she is a good flirt.
A women's choice of earwear is very personal so compliments about them are usually well taken.
Avoid, at all costs, women who wear scarfs as fashion statements.