For a simple refreshing drink, try adding a slice or 2 of lemon to a jug of water and leaving it to chill in the fridge. For something a bit more exotic, lightly crush a few strawberries and a slice or 2 of lemon in a jug, add a couple of slices of cucumber, top up with ice then leave for a few hours or overnight. Strain into a glass or, if you pour it before all the ice has melted, the chunks of ice will hold back the fruit.
Then, start to experiment using different fruits and even herbs - whatever you've got to hand or your favourite flavours. Popular combinations include Raspberry and Lime, Pineapple and Mint, Melon and Orange, Cucumber, Mint and Orange, Strawberry and Mint or Basil,, … the list is endless. And you can even use frozen or tinned fruit (in juice not syrup) as well as fresh fruit.
If you can't manage without a bit of sweetness, try adding a little honey, agave syrup, sweeteners or sugar (it will still be a lot less than manufactured drinks).
How about sharing your best combos by adding a comment?