Shopping Bags: Whenever possible --- use, reuse, and ask for paper rather than plastic bags. If you can't avoid plastic bags, reuse them until they are completely useless.
Batteries: Instead of disposable batteries, use rechargeable wherever possible.
Charcoal Lighter Fluid: Use regular charcoal, rather than the self-lighting kind, and patiently light the briquettes using crumpled paper and untreated wood kindling or a grill "chimney". Barbecuing pollutes the air and loads foods with toxic substances. If you feel you must barbecue, don't compound the problem by using lighter fluid.
Cookware: Use glass or steel pans rather than aluminum. Avoid plastic "non-stick coatings" on cookware and on burner reflectors.
Food: Ask for and buy local, sustainably grown produce and meats. Eat and shop where foods aren't encased in plastics.
Hard Water: If you live in an area where the water is loaded with minerals ('hard") and don't have a household softening system, you should be able to use soap for most purposes by adding a little washing soda, baking soda, or borax to wash water as a softener preferably before you add soap; this will tie up the minerals so the soap can do its job. To figure out how much to use, run a quick experiment, put 1/2 t. washing soda, 2 c. warm water and 1 t. soap in a quart jar and shake. If suds develop and last several minutes, the water is soft enough. If not, repeat with the same amount of soap and increased amounts of washing soda, baking soda, or borax. When suds persist, that is the proportion of softener to water you will need for future cleaning chores. Unfortunately, though, soap won't work well in laundry with hard water, so use a phosphate-free detergent.
Heating Appliances: Gas appliance flames should be blue, not orange or yellow. Have gas stoves and furnaces inspected periodically; they can be a major source of carbon monoxide and other indoor pollutants. Fireplaces must be well ventilated and their use minimized. Kerosene heaters should be avoided altogether. Install a carbon monoxide detector.
Household Lubricants: Use castor or mineral oil on hinges, doorknobs, and latches. Use powdered graphite on locks. Avoid lubricants containing solvents.
Radon: If you live in an area where this naturally occurring radioactive gas is a common problem, have your basement tested.