There's this super cute gas station attendant who I've seen before. She's there often. The bulk of her interactions with people are "$40 on 12" "Ok." "Change for 12." "Ok." I was thinking of slipping her a note saying something like "What's your number? You're super cute!" Do you think this would be a good idea?

Its better than not doing anything, but it's still pretty poor game.

Why don't you try this, go to give her the money then as she tries to grab it move it around out of her grasp until she realizes your fucking with her. Then if she laughs say "aww you have a cute laugh, your pretty hot as well, why are you working at this shitty hellhole". Remember that's ok to call her work shitty, she is well aware that it is shitty. . If she responds positively to that say "hey give me your number". This is how you positively escalate and calibrate to stay out of the creeper zone, this is because because you have the opportunity to bail out anytime she isn't receptive to these innocuous steps.

Hey

Definitely dont give her note.... IDK how in your country is at gas stations but here you need to tell number of gas pump. If u dont tell attendant asks for it, if it is that too in your country you can wait that she asks you: Number? and u can joke that you need to know her better before u give her your number or sth. Or say Ur cute, but I dont give my number to strangers, u could harass me then:D

If she is not busy i recommend u to talk with her something abt her work or sth, i do it a lot with gas station attendants at evenings bcs they r alone and bored and some 2 mins joking chit chat doesnt hurt...

GL

Just banter with her off the cuff. You don't need a "line"; if you are a smooth operator she will be able to tell. If you are not, then work on becoming a smooth operator.