New, pretty, kind, skilled
What you notice and praise about people and their things: new, pretty or clean, kind, good at something.
atarashii
polite atarashii desunew, fresh
新しい あたらしい 新しいです
Says something is new: things you've bought, a job, a shop, a phone, news; it goes straight before a noun (atarashii shigoto).
sono fuku, atarashii?
Is that outfit new?
その服、新しい?
sono fuku, atarashii desu ka?
Is that outfit new?
その服、新しいですか?
Its opposite furui (old) means not new and never describes a person's age: furui tomodachi is a long-time friend. For age, say toshiue (older than me).
kirei
polite kirei desupretty, beautiful, clean
きれい きれいです
Says something looks lovely or is clean and tidy: views, places, people, rooms, handwriting; kirei ni makes it an adverb (kirei ni shite = tidy it up).
umi, kirei da ne
The sea is beautiful.
海、きれいだね
umi ga kirei desu ne
The sea is beautiful.
海がきれいですね
Said kiree; a na-adjective despite the -i: kirei ja nai, kirei datta (never kireikunai).
Learn first: kirai
yasashii
polite yasashii desukind, gentle
優しい やさしい 優しいです
Describes a kind or gentle person or act; after arigatou, yasashii ne compliments someone for a kindness they just did.
arigatou, yasashii ne
Thanks, that's so kind of you.
ありがとう、優しいね
arigatou gozaimasu, yasashii desu ne
Thank you, that's so kind of you.
ありがとうございます、優しいですね
A separate yasashii means 'easy'; use kantan for that and keep this card for 'kind'. yasashii desu ne suits peers and people you know well; to a stranger, boss or teacher who helps you, say arigatou gozaimasu, tasukarimashita instead.
jouzu
polite jouzu desugood at, skilled
上手 じょうず 上手です
Compliments someone else's skill: X ga jouzu (you're good at X), or jouzu da ne after watching them; jouzu ni = well, skilfully. About yourself, use it only in the negative or as a goal (mada jouzu ja nai, jouzu ni naritai): claiming it sounds like boasting.
ryouri, jouzu da ne
You're a good cook.
料理、上手だね
ryouri ga jouzu desu ne
You're a good cook.
料理が上手ですね
Reply to nihongo jouzu! with ie ie, mada mada desu (casual: iya, mada mada da yo); for your own strengths say tokui. To a boss or teacher, jouzu desu ne sounds like grading them: praise the result instead (sugoi desu ne).