A reply to "How are you?" can be "I'm good, how are you?" or "I'm fine, thank you." It is polite to reply to this question with a question of your own, or with a statement about how you are doing.
- I'm doing well, thank you.
- I'm doing alright.
- I'm hanging in there.
- So-so.
- Not bad.
- Could be worse.
- Fair to middling.
- Passable.
- Decent.
- Good enough.
- Could be better.
- Not great, but not terrible either.
- manageable
- okay
- presentable
- I've seen better days
- I've seen worse days
- It could be worse
- Not too shabby
- The usual