WHEN CALL SOMEBODY:
美女= mei nv（nyu）= beautiful girl （in China, it is widely used. It is used as "Miss, madam,mam..."）
帅哥=shuai ge /靓仔=liang zai= handsome guy （wildly used，like sir ）
(Those three words are kind of compliment, everyone will like to hear those when you call them:D)
in formal occasions, better to use 小姐&先生
小姐=xiao jie= miss
先生=xian sheng= sir

DAILY TALKS:
吃饭没?=chi fan mei= Did you have dinner? (for greeting) 
好久不见！=hao jiu bu jian= long time no see! (can you tell me whether  it is  English?)/ it has been a long time since the last time I saw you!
哪里有好玩的？=na li you hao wan de?= Where to have fun?
哪里有好吃的？=na li you hao chi de?= where to eat?
厕所= ce suo =toilet
医院=yi yuan= hospital
请问... 在哪？=qing wen ... zai na?= could you please tell me where (somewhere) is ?
派出所=pai chu suo = police station
我住在...=wo zhu zai...= I living at...
你可不可以告诉我怎么去(some place)...? =ni ke bu ke yi gao su wo zen me qu...= Can you tell me how to go to...?
这个多少钱？=zhe ge duo shao qian?= how much is it?
我请客!= wo qing ke=this is my treat!
怎样找你=zen yang zhao ni = how to contact you?
...
...
if you don't know what to talk about in some exact occasions, feel free to ask ~