If i smile at her and she smiles back, thats my cue that she prolly thinks i'm cute. Then i approach and tell her i think she cute and would like to take her out some time.
Nothing super clever about the approach just relies on natural unspoken chemistry, and doesn't hurt that i have a look, frame and build that are not offensive to the eyes.
but that is not required, the way most dudes mess up is they skip the whole "she noticed me noticing her noticing me" part of the equation and will literally jump scare a woman, catching her off guard when shooting their shot. Don't just pop up on someone minding their business and start flirting. You seen the gif from the pdiddy threads, poor girl at the buffet turns around and sees a stranger telling her she got pretty eyes. probably had no clue he was even there before he started in.