Kramer

Only open the shower mixer lever to half or three quarters. This (in most cases) is suffcient to shower with, but uses less HOT water to achieve the same temperature.

Remove the friction belt from your exer-cycle.
Replace it with a cluster of old bicycle dynamos (The more dynamos, the greater the resistance)
Feed that into some car batteries for storage.

So many portable devices are left too long on charge. It's not good for them and it is costing you money. Only charge when you need to.

Turn off the TV (there's nothing worth watching on any way). Turn the lights off and have your dinner by candlelight. You'll save energy and if things go well you'll end up with an early night.

I know it's not an original idea...But on fine days, hang your washing outside. Save running the dryer for when you really have to.

Most wardrobes nowadays have a light in them. Make sure your children understand the importance of keeping the door closed after messing about in there!