A garnish is not decoration. In most drinks it is the first thing you smell and therefore a large part of what you taste. Get it right and a good drink becomes a memorable one; skip it and something is quietly missing.
Three jobs, in order of importance:
Expressing a peel. Cut a wide swath of citrus with as little pith as possible. Hold it skin-side down over the drink and pinch sharply — you should see the oil spray. Rub it around the rim, then drop it in or discard it.
Slapping herbs. Put a mint sprig in one palm and clap once. That ruptures the oil glands without bruising the leaf. Muddling a garnish sprig instead makes it bitter.
Half-rimming. Salt the outside of half the rim only. The drinker chooses each sip, and no salt falls into the drink to keep salting it.
Placement. A garnish should sit where your nose goes, not on the far side of the glass.
Browse drinks by their garnish at /garnishes/, or see the full recipe directory.