I like to add things to my water to make it taste better. A lemon or lime is a great start, but I want a bit more flavor. So I pick fresh mint from my garden and add it to lemons for a tasty treat. I've also seen people add cucumbers. Or even substitute the lemons for oranges.
The most common way to make flavor water is getting a pitcher that closes and adding all ingredients. Then slightly crush the produce you added in. After the produce is slightly crushed but not mashed add a ton of ice with just a touch of water. Then place in fridge.