I've had a lot of people asking me what I use to accurately measure ingredients for cocktails. Since a lot of the great classic cocktails I enjoy sipping (and making) call for ingredients in .25 ounce and .75 ounce measurements, and since many of the cocktails I create call for those same increments, I use this wonderful bar tool.
There are several different measuring tools on the market (as seen in the pic above), but I much prefer the ProJig by Uber Bar Tools. It provides me with 1/4 oz, 3/4 oz, and 1 1/4 oz. measurements, while the Oxo measuring cups do not. It's also easy to clean. Stainless steel jiggers work well too, but you end up with 2 or 3 different jiggers on your bar top in order to cover all of the needed measurements.
Why measure? Creating balanced cocktails is more akin to baking than cooking. A 1/4 oz. too much or too little of certain ingredients can make a huge difference in the cocktail, throwing the balance off. Furthermore, it's very difficult in the accuracy department when free-pouring ingredients like syrups, purees, and heavier liqueurs. Can free-pouring work in a craft cocktail bar? Sure it can. But I much prefer measuring. And when done properly, it doesn't have to slow you down!