In addition to these ones that have already been mentioned, I'd like to suggest some things I usually do to reduce my energy use:
- Turn off the lights when leaving a room (yeah, that's a quite obvious one, but just in case! ) ;)
- Unplug all the devices that are already charged or not being used: unplug chargers that are not working.
- Full the dishwasher when using it, as well as having a shower instead of a bath: quicker and greener!
- Turn your thermostat down: Keep the central heating at between 18-21C to have a comfortable and healthy temperature.
- And of course... use renewables!
Hope it helps!