My recommendation is to choose a thin-walled stemmed glass or crystal glass – avoid a rolled lip on the edge. The bowl should be at least 5 inches high with a moderate 2.5 inch throat. This ensures enough air space in the glass to swirl the wine vigorously and thoroughly assess the wine’s variety of aromas and flavors. The thin wall and thin lip assure you are as close to the wine as possible.
Premium glass manufacturers like Riedel, Schott, Eisch and others make many different kinds of glass; in the extreme, Riedel makes one for nearly every type of wine! As a wine guy, I have four different types of glassware: a Riesling, a Riesling/Zinfandel all-purpose, a red Bordeaux and a red Burgundy glass – oh, and Champagne flutes! That’s probably more than anyone needs. For most occasions, a good all-purpose glass is fine. Look for a Riesling/Zinfandel/Sangiovese glass – it’s great for reds and whites.
Use the stem and its base to hold the glass, avoiding holding the bowl. Holding the bowl adversely affects the temperature of the wine due to glass contact with your body heat. Swirl the wine while holding the glass on a firm base, like a table, in order to avoid spilling the wine.
To evaluate the wine’s color, hold the glass away from you at a 45 degree angle, preferable tilting the glass against a white table cloth or paper, in a well-lit room. This way, you can see all the wine at once in the glass allowing you to better assess the density of color and saturation of hue and the clarity of the wine. A clear wine is well-made (white wines can show bright stars of light below it) while a cloudy wine is a red flag; the wine may be unstable or have undergone an unintended secondary fermentation in the bottle.
Examine the color, or lack of it, of the rim of the wine or where it touches the glass. A clear rim indicates a young wine while, conversely, an orange, amber or brown rim may indicate stages of possible oxidation.