4. Don't use bottled drinks unless you have to. Bottled water - and other bottled drinks - are a major source of waste in many places. In some places bottled water is safer to drink than tap water, but if that's not the case in your area, consider using tap water instead. You can always filter the water if you don't like the way it tastes. This is more economical and much better for the environment.
If you really want to go the distance, you can nix other bottled and canned drinks, too. For example, instead of buying a case of ginger ale, why not make your own? Homemade lemonade and limeade are also great choices.
If you do choose to buy drinks by the bottle, choose large containers, rather than small ones. Get a 5-gallon container of water with a dispenser instead of buying an 18-pack of small bottles.