1. Easy one: turn the lights off in rooms when you're not there
2. Turn your lights + pc monitor off when you go to the bathroom
3. Use public transport instead of car
4. Use bicycle or walk instead of public transport
5. Eat less meat.
6. Use energy saving light bulbs
7. Buy a LED-monitor and LED-television.
8. Clear the ice from your freezer.
9. Drink water instead of coke. Is healthier too.
10. Remove all electronic devices from their power sockets when you go away for a few days.
ALL THESE TIPS save money as well. Who said being good for the environment is expensive?