From laylita.com
(you can adjust this)
Either directly in a short glass or in a cocktail shaker, combine the lime halves or quarters with the sugar and use a muddler to gently crush and squeeze out the lime juice from the limes.
Add the cachaca and lime juice, stir or shake well. If using a cocktail shaker pour the drink, including the muddled limes, into a short glass with crushed ice. If making the drink directly in the glass, add crushed ice and stir.
Serve immediately garnished with a lime slice.