To make the perfect classic negroni cocktail all you need is balance: use equal parts gin, sweet vermouth and Campari.
Pour the gin, vermouth and Campari into a mixing glass or jug with ice. Stir well until the outside of the glass feels cold.
Strain into a tumbler and add 1 large ice sphere or some fresh ice, and garnish with an orange slice. You can also add a few dashes of Angostura Orange Bitters.