Ripe strawberries are naturally sweeter than unripe. Choose or pick strawberries that are a deep red. White or lighter red shoulders means the strawberries aren't as ripe as they could be. The variety of berry determines how sweet they are. Firecracker, eversweet and seascape are sweeter than other varieties. If the strawberries you have aren't as sweet as you would like, sweeten them up.
Wash the strawberries right before you're going to use them or serve them. Place them in a colander. Run cold water over each berry. Shake the colander to get rid of the excess water.
Lay the strawberries on paper towels and pat dry.
Cut the cap of the leaves, called the hull, off the ends of the strawberries, taking as little of the berry, itself, as possible. Slice the berry in three or four sections depending on how big the berries are. It doesn't matter whether you slice vertically or horizontally. Cutting the berries exposes the flesh so the berries will release juice when exposed to the sugar.
Add 1 tsp. of white or brown sugar, honey, maple syrup, agave nectar or artificial sweetener per label directions for each cup of strawberries. Toss the sliced berries so each is exposed to the sugar or sweetener.