If you've ever made any sorta of beverage - a cocktail, iced tea or coffee, lemonade, etc - you've learned some basic science - sugar does NOT dissolve in cold liquid with a simple stir. It takes either 1) LOTS of agitation or 2) a warmer liquid. Sometimes, this is a good thing, as granular sugar is often a key ingredient to a drink that involves crushing or muddling, like a mint julep or a mojito. And sometimes, it's really annoying and inconvenient.
So, the beverage-world has long used a liquid sweetener known as "simple syrup" to incorporate sugar into drinks. It uses a basic "simple" ratio of 1 part sugar to 1 part water. Some approaches call for as much as 2:1 sugar to water, which increases efficiency, but I'd keep it 1:1, or at most 1.5:1. See, simple syrup provides not only sweetness to a drink, but also volume. AND, most cocktail recipes will presume a sugar level of 1:1, so it's best to stick with what the pros use.
1.The Stovetop Method. Mix one cup water and one cup white sugar in a saucepan, then bring to a boil and stir until the sugar has dissolved completely. Turn off the heat, and allow it to cool, and transfer to a squirt bottle, plastic water bottle, or mason jar. Store in the refrigerator for up to six weeks.
2. The Bartender's Method. Fill a corkable wine bottle halfway with superfine sugar (available in stores, or you can make your own by pulsing regular sugar in a food processor). Fill the other half of the bottle with warm water, cork it, and shake vigorously until the sugar mostly dissolves. Let it rest for a few minutes as it becomes clear again, and then give it one more shake. Store in the refrigerator for up to six weeks.
And don't let the fun stop there. Simple syrups just ache to be flavored with citrus zest or herbs like mint, rosemary, or lavender.