When tasting wine, many people will to you that the first thing you should note is the appearance. This is true, but only if you are blind tasting (ie you don’t know what kind of wine you are tasting). Otherwise it doesn’t matter. That being said, there are a couple of things to look for. The first thing is the wine’s “legs”, those clear drops on the sides of the glass. What these tell you is how high the alcohol level is. The slower the legs are to form and drop, the higher the alcohol. Second is the color. Some people will tell you that the clearer the wine, the better. Not so. Clarity depends on what kind of wine you are drinking. But color can give clues about what kind of wine it is. For example, Pinot Noir will be lighter in color than Syrah/Shiraz. Color also gives clues about age. White wines tend to gain color with age and red wines lose color.
Same goes for beer. Appearance can tell you what kind of beer you are drinking or give you clues about the richness of the beer or the carbonation. Otherwise, it doesn’t matter.
More on tasting another time.