The non-creepy socially accepted way is through body language. Strong eye contact, personal space invasion, prolonged pauses between sentences, purposeful touching of slightly risky area (for women: the lower back, forearms, etc.) all done with a clearly visible smirk.
In some context however the explicitly verbal might be effective, especially if toned down (Hey you're interesting, I want to know you better) or up (Hey, you're really sexy, do you want to go to bed with me?), but it is highly dependent on the woman.
I'm not entirely sure what's the parameter here, but I suspect plausible deniability is involved.