Battery- Make sure it starts the car on one click

Lights- Check for busted lights

OIL- Check if the oil is at the right amount

Water- Check if the radiator is well filled well

Brakes- Do they work properly and no uneasy sounds

Air- Check the tires for recommended air pressure

Gas- Always make sure that the car you rented has a full tank of Gas

And most especially prepare your self ( The designated driver )