Putting your puppy outside while you are away from home is the best way to keep him from chewing on your prized possessions while you are gone. If you have an indoor dog that is not kennel trained, then close them out of the rooms in which they like to chew.
Take an assertive management role in your dog's behavior. If you don't have time to make sure a command is carried out, don't give the command.
Do not give your dog any punishments when you are in the process of training. You should make every effort to prevent the behavior in the first place, but if your pet does misbehave, show him what he should have done instead. Training should allow you to teach your dog and connect with him; the process should focus on positive communication.
Associate a word with an action and stick to it. Your dog will remember the command if it is always the same word. Stay consistent. The more consistent you are, the faster your dog will catch on.