1.
Haven't field tested it, but would love some opinions.
Can be used day/night, but lets assume it's the day.
Lets also assume you are walking, doesn't matter what direction she is going, but if she is walking towards you it would work best.
As she comes closer to you, stop and get her to stop as well. Can just use a commanding "Wait" or "Freeze", it's up to you.
When she is stopped, hold eye contact and don't say anything for a bit longer than usual.
Then say, "I've only got a minute or so, but I can never pass up the opportunity to see whether a beautiful girl is actually interesting."
2.
"Did you know it is nigh on impossible to meet another human being without any sense of bias?"
Now you have two choices here, either you can explain by commenting on someone else in the area and then moving onto her, such as;
"Take that man over there, button up shirt, classy, standing tall, confident. Probably a super cool guy" and then you would move onto her (see below), or you could even use the "let me introduce you" and take her over to the random guy. You don't want to introduce her to someone who might give you too strong competition
Or you can move onto her straight away,
"Take you, for example. Showing a bit of leg, but not too much, just enough, wearing sandals, you enjoy comfortable clothes. I bet you would look great in heels though. [or Hair's done nicely, but I reckon it would look amazing up]"
The analysis is totally up to you and make it fun and playful, then get her to qualify herself.