Be careful to not hit the other car when opening the door.
Please open the car door carefully so you don't hit the other car.
・"Be careful to not hit the other car when opening the door."
・"Please open the car door carefully so you don't hit the other car."
説明:ドアパンチは和製英語で、アメリカ英語は同じ意味の決まり文句がありません。
上記の言い方は十分だと思いますが、風が強い日に特別な注意をしたいなら、下記の例文がいいと思います:
・"The wind is strong, so be extra careful to not hit the other car when opening the door."
・"Please open the car door carefully so the wind doesn't blow the door into the other car."