鏡に水がはねちゃったら、ちゃんと拭きなさいよ!
When water splashes on the mirror, make sure to wipe it off.

 手を洗ったら、タオルで手をふくのよ。洋服で手を拭いたら駄目よ。
When you wash your hands, dry your hands with a towel, not with your clothes.

 水を使ってない時は、蛇口を閉めましょうね。水を流しっぱなしにしないようにね。
When you're not using the water, turn the faucet off. Don't leave it running.