How's it going?

This question is similar to "How are you". The answers discussed above all work for "How's it going?" as well.

Here's another answer that will also work for "How's it going", but not for "How are you?"

    It's going well.

This is a friendly, polite answer that's suitable for coworkers, clients, and acquaintances that you haven't seen in a while.

What's up?

This question means "What's happening in your life?" But you don't have to answer honestly. If you don't want to start a long conversation, you can use one of these standard replies:

    Nothing much.

This is the most common answer. You can follow it by sharing something interesting that's happening: "Nothing much. Just getting ready for Vanessa's graduation."

    Not a lot.

This is another really common answer. It's just a bit fresher than "Nothing much" because it's a little less common.

    Nothing.

This is more to-the-point. It might make you seem a little angry or rude.

    Oh, just the usual.

Answer this way if you do mostly the same things each day.

    Just the same old same old.

This phrase means that you're doing the same things every day, and you're a little bored of it.

    Oh gosh, all kinds of stuff!

You can answer this way if your life has been really busy and exciting lately.

What's happening?

This question means the same thing as "What's up" and can be answered in the same way.