Garnishes:

Lemon Twists: Although I've occasionally seen an experienced barman cut a lemon twist from a lemon peel, most establishments prepare lemon twists en-masse. The way to do this is to cut the ends off of a lemon and use a spoon to force the pulpy fruit out of the lemon.  You then slice the empty lemon peel lengthwise into quarter-inch thick strips. When called for, take one of these strips and twist it like a corkscrew as you use it to rub the inside of the glass. When you've flavored the rim of the glass, drop the lemon twist into the drink and stir briskly.

Lime & Lemon Wedges: So many drinks call for lime wedges that it is best to have some of these prepared as a part of preparing you bar. To cut a lime or lemon wedge, cut the lime or lemon across the short way and then quarter each remaining half.    To serve, rub the wedge around the rim of the glass, squeezing gently, and drop it into the drink.

Maraschino Cherries: It's unclear whether these bright red cherries are garnishes or garbage.  Although they add little flavor when dropped into a drink, most people prefer to pull the cherries out by their stems and eat them as well.  Because of this, buy maraschino cherries with stems attached if possible.  Also, be aware that green maraschino cherries carry a very strong, very different, and very minty flavor while red maraschino cherries are sweet and tasty. If a drink calls for a maraschino cherry, a red maraschino is almost always preferred.

Olives: The traditional martini garnish, green olives should be served without pimentos (the little red thing sometimes found in green olives) and served skewered on a toothpick, plastic sword, or martini skewer and placed in the drink.  Although some drinks specifically call for black olives, if the recipe doesn't specify what color olive to use then a green olive is appropriate. 

Pearl onions: Pearl onions should be served in the same manner as olives, skewered and placed in gin and vermouth.

Celery stalks: The traditional decoration of a Bloody Mary, you should cut as little as possible from the celery, leaving the leafy end above the level of the liquid while also leaving as much of the celery as possible to be chewed on by the drinker.

Cucumber peel: To create a cucumber peel, it is necessary to take some small amount of the fruit within, cutting the peel to be approximately a quarter of an inch thick. The peel should then be curled around the rim of the glass and dropped into the drink.

Garbage:

Lime, Lemon, and Orange Slices or Wheels: Where fruit wedges are garnishes, the slices are garbage meant to decorate but not flavor the drink. Because of the shape of these fruit slices, they are also called wheels even though they are only semi-circles.  To create a fruit wheel, cut off the ends of the fruit and then slice the rest into quarter-inch thick slices. Cut these slices into halves, and make a thin cut along the grain of the fruit. To serve, slide this thin cut on to the rim of the glass.

Kitsch: Various drinks may also be appropriately served with plastic swords, paper parasols, fireworks, or any other odds and ends. Although men are often embarrased to be served such decorated drinks, we find that almost anything is acceptable on the shores of a tropical island.

Next steps:  

This article is the fourth article in a ten article series designed to transform people new to drink mixing into competent bartenders.  Click for the next article in the series, Shaken & Stirred Cocktails.