Wash it at least once a month with one of the many auto wash liquids, paying special attention to removing winter salt deposits from the undercarriage. Avoid household detergents because they're harsh and can remove the wax. A chamois does a better job of drying a car than a towel does does because a chamois is very absorbent.
Bath towels can be abrasive.
If you don't want a chamois, ask at one of the stores about nonabrasive towels used to dry a car. Don't wax a car in direct sunlight, which can cause chemicals in the wax to damage the finish. Some people think the clear coat lets them avoid waxing. But road gunk and the elements wear down that coat, which wax protects. To maintain your car's original ride and handling, make sure the aspect ratio of your new tires matches the ratio listed on your car's original tires or on the placard on the door edge, fuel filler door, glove box or visor.