I know this sounds cruel.. but when they're chewing things as puppies, a bit of cayenne pepper sprinkled on the no-no's. Dogs will always sniff something before chewing, so if they get a little whiff of that - they ain't gonna chew it!

Toilet rolls and empty cardboard boxes are great entertainment, my dogs love ripping them to shreds and scattering them all over the place. I don't care, pretty easy to sweep up once they're done and it keeps them happy