Correct way of powering Arduino Uno through a 12v Car Battery

I would like to know the correct and safe way to power my Arduino Uno in my car.

5V adapter (cell phone charger) plugged into the power socket (what used to be the cigarette lighter). Newer cars also have 1 or more USB outlets, often between the front seats in the armrest/console.

Sorry, I don't want the wires sticking out so what I wanted to do was to make it go to a switch from the battery, to the Arduino board. Just trying to keep all the wires hidden and don't want to use the Cigarette lighter.

I use an OKI-78SR-5 on my boards to convert the 12V battery to 5V. It cost more than a liner but I like to keep the battery charged.