Green tip 6: Lights out!

If you are the last to leave work, make sure you turn everything off behind you, including printers, drinks machines, fans, lights, etc. Some of your colleagues may have forgotten in the hum of a noisy office, but once most people have gone, it's easier to notice.

If you know you're likely to be the last to use a meeting room or other facility, you could always turn the lights out early.