Hello always worked for me. its easy, you should try it sometime. i worked night clubs for ahem..... not proud to say but 13 years. i have thrown out more guys for "grinding" against women that do not like it. it seems the majority of the women in the clubs do not like that approach. Unless like mentioned before they are drunk off their ass or slutty, or a combination of both. Walk away from them fast. i had several police interviews reguarding women that were wasted leaving with a guy they just met, sleeped with him, and the next day claimed rape because they felt stupid and embarressed of what they did.
seriously dude, eye contact is everything. if you see a woman you like dont stare at her but glance her way every so often and you will be able to tell if there might be a connection. i have met a lot of women in clubs (even my wife whom i did the right thing and asked her to dance) and every single one of them that i approached all i had to say was "Hello". its a perfect conversation starter. but you have to do it with a smile.
for me now, i could never pick up a girl at a club or bar anymore. since i have bounced for so many years when i walk in a club im in people watching mode. i cant help it. its kinda fun in a way because with my friends i can pick out who is going to start a fight, who is going to get thrown out even before they do something stupid, etc. even the women i can see them coming from a mile away. i know the ones who do not want to be there and were dragged out by their friends (these are the EASIEST to approach, just talk to them when their friends are on the floor without them). i know who is going to be the drunk slutty one of the group, and who is going to make out with EVERY guy in the place. thats disgusting by far seeing some half ok chick going around the club and ramming her tounge down multiple guys in the place.