Walk to work/school. This means moving house closer to work, or changing jobs.
Cook over an open fire, use straw boxes for slow cooking.
Go to sleep soon after dusk, get up at dawn - to minimise need for artificial light.
Switch off unnecessary electrical equipment - that would include this computer.
Generate electricity through wind/water/solar power. Hook up a generator to an exercise bike and do half an hour each on it every day.
Electricity to be used for absolutely essential services only - like refrigerating food (and probably TV too, for information purposes)
Eat local produce only - that means eating things in season.
Learn to ride and maintain a horse.
Make/buy a horse cart for transport.
Reduce procreation drastically - not just in third world countries, but everywhere. Target to reduce population by at least 2/3, to bring us back to the sort of numbers that are more easily sustainable through non-artificial means.

I'll start now by switching off the computer, getting back to bed to keep warm and refusing La Inglesa's advances unless we can dust off some prophylactic from somewhere.