Only put top up or down when room temp or warmer. If all ready down, leaving down over winter will not make it any worse for the wear.

Fill fuel tank. Make sure 50/50 antifreeze is less than 3 years old. If possible, put car up on blocks to relieve suspension. Make sure battery is in good condition and fully charged, or remove and put in room ambient environment. Store car in dry place without temperature inversions that will cause moisture build up on or in car and engine. An example is a wooden or insulated building like a home garage or wooden storage building. Concrete block and sheet metal buildings cause moisture build up. If you must store in block or sheetmetal buildings, keep moisture out of internal engine parts by doing the following. Fill a rag with mothballs and place in the air cleaner on top of the carb opening in such a way that all air must travel through the balls into the carb. Put mothballs in rags and stuff in each exhaust pipe. Moth balls act as a desiccant. Use an actual desiccant in place of mothballs if can. The purpose of this step is to allow the engine to breath air during temperature changes but trap any moisture entering the engine.

If rodents present, put mothballs in trays and place in interior. Although rodents eventually get use to mothballs, they will do the job for one season. Mothballs also work well to keep insect in check too.