It is a good idea to place cup holders in the car to avoid any kind of spillage. You can attach the cup holder near the air conditioner or near the arm rest.
Always keep a trash or paper bag ready in your car. You can use it for disposing off the trash from the car. It also comes in handy for those who suffer from travel sickness and are at times prone to vomiting while travelling.
A small vacuum cleaner for your car is extremely handy. You can put your vacuum cleaner in the trunk. This can allow you to quickly clean the dashboard, seats and carpets of your car anywhere, anytime.