I have much better experience opening girls/sets during day on streets, rather than night at clubs, so I want to share my experience for day opening:
What is important is to be happy or at least to have fun. You can open girls/sets by anything that you say, the idea is to be different then the boy's general openers like "hey" "what's your name" "You are beautiful" and stuffs that most girls hear almost everyday.
And thing that is more important it's good to have someone with you, like a wing, because you feel more confident and to not give a f**k if you get rejected:
So here are some crazy ways that i stopped random women and the openers i improvised:Me and my school-mate (when i was at High school) on way home walked trough a street. I saw a nice girl coming opposite me. I smiled, she returned with smile, what i did after we passed is i stopped, turned back and yelled "I'll eat you". The reaction was she stopped, turned back and smiled, so i went to her and asked her name and got her contacts.
The same day, there were elections in my country, so a girls gave me some political newspaper. It smelled like dough. While arguing with my school mate i saw two girls coming to me and i asked them:
" Excuse me, does this newspaper smell like dough" Then they smelled it and said "YES!" and started laughing then we exchanged names, asked them more questions about them and then me and my schoolmate left them and continued our way home.
My idea is that most people are serious when they walk and they usually think about problems and so on. When you stop a girl and ask her for name or open her with some usual stuff maybe it seems to be some weird that pick's up girls from streets. But when you stop a girl and say some crazy stuff, you seem to be different, you're like funny guy. Girls love funny guys.
Also one good routine is to (for countries where English is not official language) is to stop a random girl/girls and ask them in English where is some building or object, so you're playing that you're foreigner. Most girls love foreigners and are getting attracted because of that. Once me and my best friend were walking in his town. On our way we met a girl that was cute, so i stopped her and asked her "Hey do you know where is the Trakian tomb?" Shed didn't know English, only few words, so she tried to show us with signs. Then i thanked her and introduced myself:
"Nice to meet you, Kaloyan". (Note: Kaloyan is Bulgarian name that has no analogue in other languages,except Greek) then she replied me with her name and for less then a second she understood that i'm not foreigner and she laughed that i tricked her.
The same situation but with other girl:I met her in the same city. she was in hurry. When i asked her to show me the Tomb, she got confused and she then agreed. We were talking a little (Her English was good) and after the ticket seller suspected me to not be English man, after we got out the Tomb i told her i'm Bulgarian and she made the same smiley of "AHahaha, you got me" so she was about to invite me in her home and offer me something to eat and drink, but as i knew her more i wasn't attracted anymore.. so we just went to cafe together.
The analysis of the last story is. That the girl was in hurry to go to some institution, because it was going to close soon, but when i met her, she forgot about it and she led me to the Tomb (it's museum), so when i told her i'm not foreigner she remembered that she had to go there.