I think there is alot signs if the girl will let you kiss her.
During the date you just need to "read" her, you'll notice if she is atracted to you and via versa. Girl will let you kiss her in 2 occassions i think, 1st when
she is atracted to you and 2nd is if she is "ok" with you, means she isnt having negative thoughts or feelings about you ,but she also isnt atracted.
And the kiss will happen for sure, if she doesnt think youre a creep

.
Still, after first date. Depends on how atracted YOU are to her, i d give a kiss on a cheek before leaving, or no kiss at all. This will leave her with mixed feelings for sure.
One of mine lines was,
Talking with girl:
"You know what i think?Cause i know you like me, and i feel the same. I think we should do one thing/kiss. I think we should see how it feels. Because i know we are waiting for THAT moment, when music slows down, everything stops and it will happen. But i must say, that moment might not come any soon. Or when it comes, one of us wont notice it, and it will just pass. And as the time goes, and nothing happens, we will just feel akward and end up as normal friends."
worked for me.
ps. i definetly wiill try that "do you want to kiss me?" line.