Consider adding the sugar now. Sugar dissolves better in hot drinks than it does in cold drinks.
Avoid leaving the coffee in the fridge overnight, or it will taste bitter. [4] X Research source
Make sure that you stir well to help the sugar dissolve.
For a lightly-iced coffee, plop in a few cubes. For a regular iced coffee, fill the glass almost to the top. The ice will melt quickly at first, but it will slow down once the coffee becomes cold.
