How to Taste Wine
Wine is judged by color, bouquet (smell) and taste.
To taste wine properly, fill a glass one-third to one-half full. Hold the glass by the stem, tilt it slightly against a well-lighted, white background and examine it for color.
I like to do the "two fingers" test with a red wine: place two fingers behind the bowl of the wine glass and see if you can see them through the wine. If you can see your fingers clearly, this is a less concentrated wine. If you cannot see your fingers at all through the wine, you probably have a denser, more concentrated wine in your glass.
A young white wine will probably be a pale straw-yellow color. An older white wine will become darker, approaching an old gold.
A young Beaujolais, for example, will be a bright reddish-purple; a Bordeaux, on the other hand, will evolve from a deep garnet in youth to a brick red in maturity.
Next, swirl the glass, either on the table (what I call "swirling with training wheels") or while you hold it, to aerate the wine and thus release the bouquet. Bring the glass to your nose (don't be afraid to stick your nose into the glass!) and inhale the aroma. A major part of our impression of a wine comes from smell. Try to define whether what you're smelling is fruity, or flowery, or both (or something totally different).
Finally, sip and swirl the wine around in your mouth: draw a small amount of air into your mouth and let it mix with the wine. This further releases the flavor. (The slurping sound is perfectly acceptable at wine tastings!). This first taste is called the first "attack". Since your palate may have been unprepared for this opening salvo, repeat the sip-and-swirl step again (second attack), and see how different the wine tastes the second time around.
One of the most important qualities to look for in a wine is balance, i.e., that all the component parts of the wine are in harmony.