Use a paring knife or a vegetable peeler to remove a long, wide swath of peel. Try not to take too much pith with the peel if you’ll be placing the peel in the drink.
Next use your kitchen shears or paring knife to trim the edges of the peel into a rectangle or give the peel a fancier look with angled, pointed ends.
At this point, your citrus peel is ready to use. Twist it (or fold the edges back towards yourself) while holding it over the glass, peel facing the drink, and watch as the oils spray from the peel. Run the expressed peel along the rim of the glass for even more flavor and citrus scent.
You can discard your peel, place it in the drink, or place it on the rim of the glass. A nice way to enhance the look of your twist is to use a chopstick (or bar spoon handle or similar-shaped object) and literally twist the peel around it. If you place it on the stick like this for a minute or two, it will hold its spiral shape for a surprisingly long time.
To place a twist on the rim of a glass, cut a slit about an inch and a half long in the center of the peel, lengthwise. Use the slit to sit the twist on the edge of the glass.