There are many things to consider when you are on the road, be it in your own car, be is a rental car, or be it a taxi.
If it is with respect to a rental car or a taxi, you need to follow the rules as prescribed by the cab company or the rental car company.
These guidelines, nay advices, can come in handy all your life, in any given situation while being on the road.
Making sure that the car is checked:Before you embark just make sure that the car is in good shape.
Planning will primarily include planning the route, planning for food supply, planning for fuel supply, figuring out gas stations along the planned road, etc.
Supplies (only for long journeys):supplies should be a concern if the journey is fairly long.