Developing good chewing habits is all about making the things you want your pup to chew easily available and rewarding!
Nearly all your pup's food and play should come from toys.
Good toy qualities:
Large enough for your puppy's size. (Your pup should not be able to swallow or choke on it. If it's even close, chuck it!)
No strong resemblance to things you DON’T want your pup to chew on. (If you have kids with stuffed animals, you might want to reconsider giving your pup stuffed toys, at least until he's older.)
2+ large holes or no holes. Toys with only one large hole present a rare but serious hazard of trapping a dog's tongue.
Some toys should only be given to your pup when you're playing with him or otherwise supervising him.
These include stuffed toys, toys made of fabric, toys with anything your pup could chew off, toys with squeakers inside them, etc.
Have a basket of "Together Toys" that makes it easy to take out and store these kinds of toys!
Young puppies and adolescents should always have a durable chew toy in reach (not soft/stuffed/rope toys). This helps them get the urge to chew out when they need to and keeps them safer if you're not there to supervise.
Have these available in his crate, on floors of rooms, on socialization trips to public/friend’s houses/etc.
If something appropriate is not available, your dog is more likely to chew something inappropriate.
Choose medium to firm plastic or rubber designed for dogs. Ask your veterinarian for their recommendations on what's safe for your pup's teeth.
Reward your dog's toy play!
One great way to encourage chewing and playing with toys is to give your pup enthusiastic attention when he picks something up!
Pet, play, and praise when your pup picks up or chews a toy. If he drops it, see if you can get him to pick it up again and then give attention! (If he walks away or gets mouthy, stop petting.)
Chewing Inappropriate Objects
Teaching & reinforcing GOOD habits and what is good to chew is your best defense against naughty chewing.
Puppy-proof your puppy’s areas so the most appealing objects are the right objects! You can put movable things in closets or in storage bins, and you can use exercise pens or other barriers to block furniture.
Once your puppy is loving his chew toys, you can begin introducing some of the objects you'd like him to leave alone.
If you catch your puppy reaching for the object, interrupt him. The level of interruption will depend on your puppy. Ideally, you can say his name and redirect him to something appropriate. For confident puppies, you might briefly try clapping, saying "ep ep", etc. Avoid escalating to shouting or any physical punishment.
Puppies are in many ways like very young kids, and it's not fair to ask them to leave certain things alone. Instead, it's better to keep those things out of reach until they're older and the world is less new and exciting. (We're looking at those 15 extra throw pillows...)
If your puppy gets an object you don't want him to have, avoid chasing him. This quickly becomes a game. Instead, try one of these:
The Counting Game
The goal is that your puppy hears you counting and leaves the thing he has to come get his reward. You can then pick up the thing he had while he’s eating or, if outside, move away from it!
First teach your puppy that when you count, treats are happening. Start counting and place a treat on the ground for each number.
Stop counting only once your puppy starts eating.
Practice when your puppy doesn’t have things at first!
Act really interested in something else (group gathering, if you can) and see if your pup will come over.
Start playing excitedly with another toy. (Save favorite toys for training and for times like this!)
Of course, if your pup has something dangerous, do what you need to to get it away from him. All these methods can reinforce picking up inappropriate objects! If your pup gets more attention for picking up naught objects instead of his toys, guess which one he's going to choose! This is why heavy reinforcement of appropriate chewing is so important and so helpful :)