First good way to teach my children to be eco-conscious is to explain to them what it means and show by example. Turn off lights when not in use, turn off water in between brushing teeth. Shut off things when not in use. I've shown them to learn how to donate things when they don't need it no more and clothes when they've outgrown it. To recycle their water bottles or paper.

Reminding them to shut things off when not in use. An setting a good examples.

By doing and teaching them to donate stuff they outgrow or dont need.

The same way you should teach them anything - by doing. Just lead by example and explain to them why you're doing what you're doing and why they should care about the earth.

I have my kids shut off the water while they are brushing their teeth.

Talk about the ways you are eco-conscious and show them while you do it.

To always remember to shut off lights when they are not in a room.