The next time you make hard-boiled eggs, save the water you boiled them in. After you let it cool, the enriched water (full of calcium from the eggs) becomes incredibly nutritious fertilizer for your garden.
Sometimes when you're on the go, it can be impossible to not purchase bottled water. If you must buy bottled, choose locally sourced water instead of water that's from a faraway, exotic place. The less the bottled water had to travel to get from the bottling plant to the store, the less fuel and energy it took to make it happen. Your bottled water shouldn't have more frequent flier miles than you do.
Many of us have a junk drawer at home full of condiments that automatically come with our takeout purchases. If you don't eat artificial sweetener, you can use the little pink and yellow packets to keep your clothes clean. The next time something greasy spills onto your clothes sprinkle it with artificial sweetener. The ultrafine powder will absorb oil and help make sure your clothes look their best after you wash them.