When I was a bartender people always commented that I made the best mixed drinks. One of my requested mixed drinks was my version of the Amaretto Sour. My “secret” was the addition of 7-Up which I think gave the drink a gentle fizz that broke up the syrupy sweetness of the drink. I usually made my own sour mix, which was nothing more then Country Time Lemonade (another “secret”) or would mix lemon juice with some granulated sugar -- and shake vigorously. You can also use store bought sour mix.