Professional wine tasters follow basic steps you can master, too.
Pour: Pros use simple glasses to evaluate wines, because they want as little distraction from the wine as possible. That means no elaborate cut-crystal or opaque glasses. Pour only about 2 ounces (¼ cup) into an 8-ounce stemmed glass so there's room to swirl.
Look: Appearance and color tell you a lot about a wine. Intense, deep color―particularly in a red wine―indicates how full-bodied it will taste. Although there may be sediment in older bottles, wine should be clear, with no haziness or cloudiness.
Smell: Swirl the glass to release aroma and bouquet, then put your nose just inside the glass and inhale. If you can't detect anything, cover the glass with your hand, swirl, uncover, and immediately inhale. Try to detect the wine's characteristics―is it fruity? Earthy? Floral? Woody? Within those categories, you can further refine your description. For example, if it's fruity, do you detect citrus, berries, or tropical fruits? For help, see University of California at Davis professor Ann Noble's Wine Aroma Wheel.
Taste: Many professional tasters suck in a little air with the wine, then slosh it around in their mouths. You risk appearing ill-mannered, so this technique works best at a real tasting―not at the dinner table. Remember to breathe in and out when you are sipping to aerate the wine and enhance the flavor. During tasting, consider body and texture, sweetness or bitterness, acidity, tannins, and overall balance. Concentrate on the wine's "finish"―how long its essence remains on your palate after swallowing.