Like Kristal said, you're thinking about this all wrong.
You need to be the guy that makes practically all girls they talk to want to go home with them on the same night; instead of looking for girls that look easy
And no, it's very rare that you can tell if a girl is out to go home with someone on the same night just by looking at them.
You need to play it so that when you're escalating with any girl, they want to go home with you that night, build up that much rapport n comfort that they see nothing wrong with headin back to your place for the night.
You'd be surprised with how many times you'll hear a girl say in the morning "I can't believe this just happened, we only met last night"
with regards to systems for ONS' & SNLs, it's just pretty much just normal game, except once you have your k-closes, keep escalating and comfort building. When a girl feels comfortable enough with you, she'll happily come back to your place.
Or, if that doesn't work...you could always introduce them to Sambuca
