Slice the strawberries and put them in a bowl. Sprinkle 1/2 cup of sugar over the sliced strawberries, and stir with a spoon. Set aside for 1 hour at room temperature, so the strawberries will release the juice and the sugar dissolves. After 1 hour, press on the strawberries with the back of the spoon so they release even more juice.
In a saucepan, combine 3/4 cups of sugar and 1 cup of water. Bring to a boil, then remove from heat and stir, so the sugar is dissolved. Set the sugar syrup aside and let it cool.
In a serving pitcher, pour 1 cup of freshly squeezed lemon juice, sugar syrup and 8 cups of cold water. Add the strawberries with their juice and lemon slices.