Using a decanter may improve the enjoyment of a wine, particularly for young tannic wines, as this will "wake up" the wine so that it reveals its full personality. But what if your wine is very tannic, or you're in a rush?

The answer is to use an Aerator. An Aerator separates the wine during the pouring process and distributes the wine around the sides of the decanter. This action speeds up the process of oxygenation in order to stimulate and free the wine's aromas.
 

Essentially wine stocks three types of aerator - one made from glass, one from silver plate, and one made from pewter.  Not all wine will need aerating, so I would advise you to first try the wine in order to ascertain whether or not the wine will benefit from aerating. Typically, young full-bodied and/or tannic wines will benefit from decanting and aerating, but it should be fairly obvious once you've tried the particular wine. It's important to stress aerating a wine that does not require aerating will have an adverse affect on the wine, so don't aerate if it's not required.