Answering “How are you?”
“I'm fine, thank you” isn't wrong, but native speakers usually answer more casually. ・Pretty good, thanks! How about you? ・Not bad! How's your day going? ・A little tired, but good! The key: ask them back.
Pretty good, thanks! How about you?
いい感じ、ありがとう!そっちは?
Not bad! How's your day going?
まあまあ!今日はどう?