1. Fresh lemon or lime juice works best for this recipe. You can use frozen juice too as long as it is not pre-sweetened.
2. You can make large batches in a pitcher and refrigerate to consume as needed.
3. Adjust the balance of lemon juice to brown sugar as per taste. If you like more tartness add more lemon juice.
Likewise, for more sweetness add more brown sugar.
4. I have always felt that the brown sugar dissolves easily. But, you can always heat the water and add sugar to it to dissolve quickly.
You will need to cool down the sugar syrup before serving.