When Kari first joined our household, I learned very quickly why some Beauceron folk referred to Beauceron puppies as "Alligator Pups". He ate everything. The entire bottom shelf, books included of my wooden bookcase, Barbies were constantly sacrificed to the puppy god, the wooden stair railing, my bent-wood rocking chair, a cell phone (snicker), two twenty dollar bills (although we stopped him before he ate the rest of the wallet), the inside of our sofa (??) and the bottom pieces of my rocker/recliner; apparently while he was supposedly dozing under my feet.
Limit His Freedom
The first thing to do with a teething puppy is look into crate training. Crating your puppy will keep him away from the deadly things he'd love to chew to pieces when you aren't looking (like electrical cords of appliances that are still plugged in. Ozzy - 3, Vacuum Cleaner - 0).
Show Him What to Chew
Chew toys, Bully Stix, and other gnaw-ables are going to be your best friends. I know it may be tempting to just let your pup chew on an old pair of socks, or old leather shoe, but try to resist. At this stage of your puppy's life, allowing one shoe or sock is tantamount to allowing ALL shoes and socks in his mind.
Positively reinforce chewing on things he is allowed to have with praise, and petting, and try to identify each item: "Is that your stick? Good boy!"
Negatively reinforce his chewing on inappropriate items by removing the item and saying "No, that is mine." and exchanging it with a proper chew toy: "Here is your ball, good boy!"
Frozen rubber teething rings will help ease the pain of cutting teeth when your pup has to be crated for safe-keeping while you are either busy or out.
There's no cure for the teething stage (unless you adopt an older dog), and it can last from age five months to over one year (or longer), but you can minimize the damage done. Be vigilant, remember my favorite mantra "This too, shall pass", and start collecting chew toys.