Avoid bottles that have any wine residue near the foil covering the cork, as those wines may have been damaged by heat.
Check that bottles are filled to within an inch of the bottom of the cork. If a wine smells or tastes sour or musty, it may be due to a bad cork. Such "corked" bottles are not uncommon, and any reputable dealer will gladly exchange them.
When STORING wine:
Wine should be stored on its side in a cool, dark place where the temperature is fairly constant year round. Unfinished bottles of wine will keep for up to a week in the refrigerator.
To bring a refrigerated red to drinking temperature, let the bottle stand out for 30 minutes or microwave a single glass for about 10 seconds.
Open bottles of wine will last longer if the air is pumped out with an inexpensive device sold in most wine stores.