You will need
½ cup (125 ml) tequila
⅓ cup (80 ml) triple sec liqueur
¼ cup (60 ml) lime juice
1 lime, cut into wedges
a small saucer of flaked salt
Shake all the ingredients with a handful of crushed ice in a cocktail shaker or stir in a jug.
If using the salt rim, run the cut side of a lime wedge along the rim of the glass. Turn the glass upside down into a saucer of flaked salt.
Pile the glasses high with more crushed ice and add a lime slice to each.
Divide the Margarita mixture amongst the four glasses, pouring it in over the ice.