To make homemade lemonade, you'll need to create the lemon concentrate. To do that, combine lemon juice, lemon zest, sugar, and water together. You can either add this to a pitcher and stir to dissolve the sugar or cook it in a saucepan until the sugar has dissolved. This is your lemonade concentrate. To serve, add ice to a glass along with lemon slices. Pour in some of the concentrate with some additional water or club soda (for a fizzy lemonade).