Much has been written about wine tasting, and that technique and
     vocabulary apply quite nicely to beer, as well. Of course, beer is a
     more complex beverage and its evaluation covers some additional
     ground, but the concepts are the same. The biggest change most
     drinkers must undergo is warming up their beer. Ice cold beer numbs
     the taste buds and doesn't allow the beer to develop its full flavor
     potential. In general, pale beer is best served at cooler
     temperatures than dark beer, and lagers cooler than ales. Start with
     40-50F (5-10C) for the cooler beers and 50-60F (10-15C) for the
     warmer ones.

     Beer should be evaluated using four senses: sight, smell, taste,
     feel. Always drink beer from a clear glass to fully appreciate it.
     Look at it and note the color and clarity. Hold it up to a light if
     necessary. Take a good sniff from the glass to get the aroma or
     bouquet. Taste it, swishing it around in your mouth, and notice its
     body and flavors. After swallowing, notice any aftertaste or finish.

     You should be noticing things like:

     Was it golden, amber, black?
     Clear or cloudy?
     Did it smell sweet, malty, flowery, alcoholic?
     Did it taste bitter, sweet, tart, smooth, roasty?
     Did it feel "thick" or "thin" as you swished it around?
     Did it leave a buttery taste, nutty, fruity?

     With additional experience and some reading you will begin to develop
     not only a sense of what you enjoy, but what marks a truly good beer
     from a bland or mediocre one.

     Also, it is usually a good idea to try a beer more than once. Get it
     from different sources, try it when your in a different mood or
     setting, wait for a full moon, whatever. Many factors will affect
     your overall perception, so be flexible. Be aware, as well, that
     tasting many beers at once is not a good idea. The taste buds begin
     to tire and send confusing impressions.