Everyone knows 你好 (Nǐ hǎo).
It's the de facto greeting in Chinese, and one of the first phrases you learn when starting out.
There are other ways to say hello Chinese, however.
Here I'll show you five greetings that you can use to give you a break from the old standard.
This is a greeting that is generally used by the older generation, and when someone asks you this they're asking after your well-being - i.e. Have you eaten? Are you full/satisfied? Is everything OK?
Even if you haven't eaten yet, a polite response would still be something like 吃飽了, or 吃了，吃了！
Just like in English if you bump into someone in the street and they ask how you're doing, you'll still reply positively even if you're having a bad day (usually).
The phonetic equivalent of 'Hi' and used exactly the same. T. Rex below demonstrates how to use 嗨 in a sentence:
Just like 嗨, 嘿 is the phonetic equivalent of 'hey'. Something you've probably noticed is that both of these are familiar characters (海 'sea' and 黑 'black') with the radical for mouth 口 added, which in this case indicates these are phonetics.
A greeting, just like 'hello', but another usage you will hear, especially if in Taiwan, is to get someones attention. If you want to get a service person's attention in Taiwan then use this, comparable to 'excuse me'.
如何 has many meanings, like 'how', 'why', 'what', but you can also use it as a greeting among friends. If you come across a friend while out you can say:
If you haven't seen your friend in a while you can say:
You can also mix it up a bit and add 嘿 and 嗨 from above:
I've tried to pick what I think are the most common alternatives to the boring 你好, but if you know any others, or any regional greeting that aren't listed then please post them in a common below