Taste your strawberries before slicing; if they’re not incredibly sweet, add more than 1 tablespoon sugar.
The longer you allow the strawberries to stand with the sugar and tequila, the more flavorful they will be. You can mix them the night before and refrigerate until serving.
Rum can be substituted for the tequila. Or, to make this a kid-friendly dessert, leave out the tequila altogether.