Here goes... *deep breath*
1. Turn lights off when you leave the room
2. Turn appliances off when you're not using them (don't leave them on standby)
3. Use energy-saving lightbulbs
4. Only charge appliances (such as phones) for as long as they need
5. Don't drive when you can walk/cycle/use public transport
6. Only fill the kettle as much as you need (or have a cold drink)
7. Only use the washing machine when you have a full load
8. NEVER tumble dry - put clothes on the line if it's nice, or use a clothes drier indoors and open the window.
9. Have cooler (and shorter) showers
10. Put a jumper on before you turn the heating on
11. Take a layer off before you put the air conditioning/fan on
12. Turn your thermostat one degree lower
13. If the weather's nice, go to the park instead of watching TV/listening to music/playing computer games
14. Turn your washing machine to 30 degrees (or lower, if it'll let you)
15. Go for a run instead of to the gym
16. Get an energy meter/monitor installed to keep track of how much you're using
17. Invest in energy efficient equipment if you can - such as the boiler, washing machine, dishwasher etc. These things are expensive but save money in the long run.
18. Insulate your loft
19. Get double glazing
20. Don't leave the fridge door open if it's unnecessary
21. Allow food to cool before putting it in the fridge
22. Match the size of the pan to the size of the ring on the hob (this prevents heat from being lost either side of the pan)
23. Open the window before you put the extractor fan on
24. Insulate your hot water tank
25. Fit draught proofing products to your doors, windows and keyholes
26. Accelerate and brake smoothly when driving
27. Switch to a renewable energy company (doesn't necessarily save energy, but it doesn't damage the planet so I'm keeping it in)
28. Don't put furniture in front of radiators as it will block the heat
29. Turn the thermostat on your hot water tank down to 60 degrees
30. Put the plug in the basin when running water (especially hot water)
31. Put a lid on saucepans to stop heat escaping
32. Keep your fridge in a cooler room such as the garage
33. Defrost your freezer regularly
34. Put a mirror opposite a large window - it'll make maximum use of natural light
35. Use thick curtains
36. Put rugs on the floor
37. If you're going on holiday, turn the thermostat down (but not completely off in order to prevent pipes freezing.) Be thoughtful towards pets: don't turn the heating down if you are leaving them at home.
38. Don't overload the fridge/freezer
39. Only use the dishwasher for a full load.
40. Don't open the oven door too often when cooking food
41. Use the microwave instead of the conventional oven when you can
42. Leave enough space between your fridge and the walls - trapped heat can affect efficiency
43. Decorate with pale colours. This means lower lighting is required.
44. Keep light bulbs clean
45. Go to bed earlier in the summer. This means you will be awake for a smaller portion of the time it's dark, and so will use less electricity.
46. Insulate your hot water pipes
47. Unplug your laptop when the battery is charged to 100%
48. Turn down the brightness setting on your computer so it uses the battery more slowly
49. Put an extra quilt on the bed instead of using an electric blanket/hot water bottle
50. And finally... any of the tips from my article '20 ways to save water' (here: http://goodliving-blog.blogspot.com/2010/07/20-ways-to-save-water.html) will also help save energy, which is used in transporting the water to your taps, and also for heating it up.
Phew. That was tiring. Think I'll have to switch the kettle on and watch a bit of telly...