I am not a native speaker, but i would use these: Hi, how are you doing? Hello! How're things (going) (for you)? How's it going? How's everything? How are you getting on? You can use multiply answers like: I am ok, thanks! I am very well, thank you! Great, thank you! Things are great! Pretty good. It's going well. etc.

I agree that they are banal but they are perfectly acceptable.

Instead of using banal phrases you could use these fun phrases instead to say "hello." "Hey, what's good, shawty?" or "just "what's good?" "What's up with it?" or just "sup?" Instead of the banal phrase "how are you?" you could use these: "What's poppin'?" or "what's up with you?" Instead of saying "I'm fine, thank you." you can say: "I'm good." or "everything's alright."

The above answers are really the best and they sound nice as well. But for what it is worth I usually say "Hey, what's up?" and if someone says the same to me I respond by saying "Not much, what's up with you?". It is a casual way of greeting.

How have you been ? Hi, what's up ? Hello, what's new with you ? Answers : Hi, I'm good Hi, I'm great Hi, things are great Hi, everything's cool Granted some of these may be more colloquial than 'correct or perfect ' English but they are widely used and acceptable to most