...to not treat everything as disposable?
In some regards, my kids are on top of things. We don't use disposable napkins, plates, utensils, etc. at home. Their lunches are all packed in reusable tupperware (they even bring silverware and cloth napkins to school!). They're forever digging through the recycling for the right size box for a craft project and have even started glue stick recycling boxes in their classrooms at school.
The area where we're weak is possessions. They think nothing of getting little plastic toys -- which always break in the first two minutes -- then throwing them away. DD's worst habit is clothing. She'll have to have something, then decide it's not cool and never wear it. (Lucky for me we get a lot of her stuff 2nd hand at the thrift or consignment stores.)
The boys aren't as bad about clothes. Theirs are all hand me downs from an older friend and they're boys - they'll wear anything! For them it's toys. They'll get something, then lose half the pieces and it always ends up in the trash.
So how do you get kids to not treat everything as disposable / throw everything away??