Port wine should be stored in the same way as any other fine wine, and whilst a proper wine cellar at home would be the perfect solution, few of us have this facility.
However, you can store Port perfectly well at home in a cupboard. The most important consideration when storing Port is to keep it away from direct light in a place which doesn't have large fluctuations of temperature and ideally where the temperature does not exceed 15ºC (60ºF).
Storing Port at temperatures above this level may be detrimental, resulting in the Port ageing too quickly.
As with all fine wine, to keep it in optimum condition all Vintage Port should be stored lying down in order to keep the cork moist. Vintage Port bottles have white splash of paint on one side which should be always kept uppermost when laying down the bottle.
In this way, the natural sediment in the Port is always maintained in the same position. For this reason, before opening a bottle of Vintage Port, always stand a bottle of Vintage Port for a few hours to facilitate easier decanting.