Greeting English

I've been studying in CA for two months. Sometimes, I found it is difficult to greet with other friends. It's not a good idea when you encounter with one of your friend just saying "how are you" like the servant in the supermarket. 
 
 
Therefore, I conclude some useful greeting sentences. (ask  how of someone)
 
1. How's it going? 
 
answers:
 
1) good.
 
2) Pretty good.
 
3) Not bad.
 
4) Not so good.
 
5) Not good.
 
but you can't answer this use "I am fine" it will be a bit strange. Anyway, I always answer this in I am fine.
 
2. How are you? ----if in the textbook, you will say "I am fine" ok, you will say " I am good, and you?"
 
Then some different answers:
 
1）"pretty good." 
 
2）“Not bad".  ---You can use this if you are feeling just ok or so-so.
 
3) I am fine. ----We always use this.
 
3. What's Up? 
 
One way:To reply this you should use a cheerful voice":Not much!!"  or "Nothing much!" --This means you are free and able  to chat.
 
Another: what's up? means "hello or hi" you can also reply this for "hello"
 
Third way: you can just answer this by "What's up?" It is just like the "hello" 
 
 
Tricky: Always I heard someone said " it is a little bit tricky!" I don't understand the meaning of tricky. 
 
Tricky means ”机警的，狡猾的，有难度的“；
 
 
Got it?

补充：综合编程 , 其他综合 ,