Say someone's good at something
Use this to say someone is good at something.
JLPTN5
[noun] が 上手です~ ga jōzu desu
someone is good at [something]
Example Sentence

You're good at singing!
The skill you are good at is marked with が, not を, which surprises many learners. 上手 is a な-adjective, so it takes です in polite speech. It usually describes another person's skill rather than your own, since calling yourself 上手 can sound boastful.