Be a conscientious shopper. Buy products with as little wrapping as possible or with recyclable wrapping. Buy products made from recycled materials. Keep your cats and dogs indoors or on a leash. Cats are responsible for killing hundreds of thousands of birds each year.
Dogs are responsible for countless deer and other mammal injuries each year.
It is not their fault, they are following their hunting instincts. Their human partners have to be responsible enough to keep them indoors or restrained at all times to prevent these unnecessary wildlife casualties. Turn your thermostat down in the winter and up in the summer. Heating and cooling often requires fossil fuels which contribute to air pollution and global warming. You should also insulate and caulk around windows and doors.