Fresh lime juice is not hard to come by and neither should a great tasting daiquiri. Being such a simple drink to make, it boggles the mind that someone charging you a great deal of money in exchange for bartending lessons would teach you how to make it incorrectly. See how simple the process really is here.
2 1/2 oz aged rum
3/4 oz fresh lime juice
1/2 oz simple syrup
Shake with ice.
Double strain into a chilled cocktail coupe