忘れないようにね

don't forget to

→ 忘れる
phrase Rare #36,679
don't forget to A friendly, casual reminder. It literally expresses the idea of making sure not to forget.
JA: 出かける前に、電気を消すのを忘れないようにね。
EN: Don't forget to turn off the lights before you leave.

部屋の開ける忘れないようにね

Don't forget to open the window in the room, okay?

帽子忘れないようにね

Don’t forget your hat.

薬を飲むこと忘れないようにね

Don’t forget to take your medicine.