While I'm not an
expert on wine tasting, I have
indulged in the activity from time to
time. Here are a few tips that I have found
useful during these excursions. Follow these, and you might not look like such a
rookie.
My experiences have been limited to the Niagara region in Ontario, Canada, with a short visit a couple of wineries in the valleys of British Columbia, so that might temper some of this as well. I tend to visit in early autumn, because it's so darn pretty in that region.
When you first arrive at your winery of choice, be sure to read the small write-ups about the winery's history. Or better yet, listen to the summer help tell you about it, it's polite and it gives them something to do for minimum wage. After paying this five minute homage, you'll be able to finally sample some of the fine wines available at the particular winery, Start with the lightest wine, such as a Sauvignon Blanc or Pinot Grigio if available, then perhaps advance to the reds. Here you can choose from such wines as a Sangiovese or Pinot Noir. Don't feel silly asking which is which; I'm still not sure myself, and these wineries are more than tickled to point them out to you.
The whites will freshen your palate and get you ready for any of the heavy wines, if you choose to indulge. I find rinsing with water can do the same trick, if you're rationing your samples. :) There might also be small cube of pastry or bread for the same purpose.
Most wineries give you a small amount of their wares at a time, while others will let you savour a full glass or two of select wines. My personal preference is the little samples; it allows you to explore more tastes, and in reality you're getting the same amount of alcohol anyways.
Before tasting, swirl the wine around the glass and notice how "thick" the wine seems. This is what the experts call the legs. Thin watery wines aren't as nice as wines that cling to the sides and drip slowly down. A wine with good legs will be more pleasant to drink, and will impress your culture-less friends. Swirling the wine allows for it to "breathe", and prepares the taster to smell the wine. You can tell a lot about a wine from the smell, and it'll give you a great idea of what the wine will eventually taste like (yes, you will get to drink it soon). There really isn't a preferred smell as far as I'm concerned, just your own personal taste I guess. My preference is the somewhat earthy smells, especially the vanilla and/or oak varieties. They tend to make for a very, very enjoyable wine, IMHO.
When you've done all of this, and to make it look like you know what you are doing, take some wine in and roll it around in your mouth. Let it hit all of your taste buds, even under your tongue. Make some appreciative noises, and nod your head knowingly as you swallow. Yes, swallow. You don't necessarily need to spit it out on these excursions, because really... it's a disgusting act anyways. Smile, but do not grab for another glass too soon! Looking eager might come across as a sign of inexperience, if you're worried about these types of things. Besides, take a stroll outside for a bit, the surroundings for most wineries are worth the visit alone!
Be sure to pace yourself if you are planning on buying any wine, as from my experience the combination of these luxurious surroundings and large amounts of alcohol tend to make you think you are more wealthy than you are. Also, avoid at all costs any trinkets such as coasters, paperweights and corkscrews. If you won't ever use it again, save your money for the wine.
What's somewhat surprising is the fact that people actually do this professionally. Courses are offered and big money is paid for talented individuals to give their "educated" opinions on the wine that is tasted. Personally, I say just go out and find the type of wine you love, but don't stop there. For years I enjoyed the fruity varieties, now I'm more of an earthy, oaken type. Times change!
One final note: arrange transportation ahead of time. You may think you can handle a few small glasses of wine, but you'd be surprised how fast you can feel it, and there's no sense ruining a nice day out at some lovely wineries by getting killed on the trip back home.