Catch the dog in the act of doing something, and make it known to them it's bad. Use the same words, same tone of voice, and eventually if the dog isn't terribly stubborn you should get somewhere.
However, be aware he doesn't accuse you back.
You: "Bad dog! Bad dog! Chewed on the table! Bad dog!"
Dog: "Who are you to judge me? You humans, you've had genocide, war against peoples of different creeds, colors, religions! And I chewed on the table? Is that a crime?"
Anyway, you'll want to do what people said. Keep stuff out of range, play with him A LOT. Make sure to punish him if he does something bad - first by calling out, and if that doesn't work after a handful of times, you can grab him by the neck (that bit that's only skin) pull him away from whatever he's chewing on and say he's a bad dog again.
I'd say look into dog trainers, too, but that didn't do a lot of good for our dog so *shrug*[/QUOTE]
It's also difficult if your dog is like mine was and has those color marks that look like eyebrows. You get mad, they look at you like
and you're like I'M SORRY.
Also also, playing is always good. Or a walk. Help the dog lose some of that energy that's being used to rip things up.