First of all I think approaching hostesses is really good for begginers because they are paid to promote the club and they will talk to you.
You don't need any opener , just go in front of a club and they will talk to you.
I'm begginer and sometimes i have fear to approach a girl , but it's easy with hostesses because you go with a vibe that says "I'm here to see what club is offering , i'm not here to pick you up"

Last week i went to a club and approached a hostess.

Me : hi, what are you offering
hb : we have new coctails....*stopped her*
me : ah , i thought you want to give me your number so we can go have a dring *laugh*
hb : *laugh* sorry i have a boyfriend
me : i didn't know that we are dating but thanks for informing me *laugh*
hb : *laugh*
me : well i gotta go now to meet friends so see you tomorrow on a date?
hb : see you
*i went inside with friends, had few drinks and i went back to see her again*
me : hi love , it's me *laugh*
hb : *laugh* you are persistent
me : well i try to get what i want , but you have bf so i don't think it will be problem
hb : i don't have bf i just said that to turn you down
me: oh i see..well in that case date for this weekend?
hb : i can't get rid of you , can I? *smile*
me : i'm like a leech *laugh*
hb : *laugh* here is my number xxxx
me : you made the right choice , you can get rid of me after one date * laugh * see you
hb : *laugh* see you soon *smile*

2 days ago we went on a date , to night swimming..we had fun , drink beer etc..i managed to kc and we will go on another date...