Switch to LED lights. They cost less to run and last longer than any other bulb.
Sprinkle dry tea leaves to deodorise problem areas such as your cat litter tray.
Choose rechargeable batteries and a battery charger to cut down on disposables. Eventually recyclable batteries reach the end of their life too but they can be recycled – local recycling policies vary so check with your recycling facility.
If you only need a tool or piece of equipment infrequently then instead of buying one, save resources by asking a friend or neighbour if you can borrow one. Or check online for a lending club, such as Streetbank.