Things heard while tasting:
“It’s very young.”
“That needs to lie down for awhile.”
“This needs about 5-7 years.”
How to Taste
Look
Pick up your glass from the stem (so the heat of your hand doesn’t affect the wine) and observe the color of the wine, particularly at the rim. What color is it? Syrah will be more purple where a Cabernet Sauvignon is red.
Swirl
Swirling the wine around your glass allows it to be exposed to more oxygen. Ever heard of people "letting a wine breathe" or wonder why Williams-Sonoma sells those expensive decanters? Same idea, just speedier.
Swirling also allows you to check out the alcohol content of a wine by looking at the legs. The longer the legs, the higher the ABV.
Smell
I used to stick my entire nose in the glass and take a big whiff. Now I usually put my nose half way down on one side of the glass and take several smaller sniffs. Try both and see what you smell from each.
Taste
Now that you're spent a moment or two with the wine, you actually get to put it in your mouth! Don't take a big gulp, you just want a sip. Let the wine coat your mouth. What do you taste? Does it make your tongue fuzzy? What about after you swallow? Don't worry: there are no wrong answers.
Fun fact: food changes how a wine tastes!
Spit
Don't like the wine? Feeling tipsy? Take a look on the counter for a spit bucket. No one will judge you! The pros never swallow.
Tip: Most of the red wines you're tasting shouldn't actually be drunk for a few years. People will often say a wine taste "young," which means the tannins haven't settled down yet. Aging a wine changes (read: usually improves) a wine's taste. This doesn't work for all wines forever. Laying down your Sauvignon blanc for a few years is a bad idea. You'll most likely end up with vinegar.
Tip: ask questions! How long was a wine in the oak? Where it was grown? What varietals are in a particular blend? Pourers like people who are engaged! Happy pourers increases the likelihood of heavier pours and pours of wines that aren't on your scheduled tasting.
Tip: write down what you think of each wine to help you decide if you want to buy anything at the end of the tasting!