Play or take your Shih Tzu for a walk to work off excess energy and provide plenty of toys and chews, rotating them frequently so they remain interesting. Provide a good "puppy-proofed" area (behind a baby gate) that is safe for him to explore, and do not allow him unsupervised opportunities to get into mischief. It is much easier to reinforce desirable behavior than to break bad habits.
Crate Training
The crate should not be a place of punishment but a sanctuary where your dog can retreat to rest and be secure. Provide toys, treats, and chews to make the crate a pleasant place. It helps to put the crate where people are during the day, or in a bedroom at night. This was the dog will be safe but not lonely. A radio or television can help to keep the dog quiet when you are out. Play with the puppy and take him out to eliminate before you confine him to his crate, and do not leave him there for such a long time that he has no choice but to eliminate in the crate. If you will be out for extended peroids, you may want to puppy-proof a small room, or use an exercise pen to reinforce your dogs natural desire to keep his bed clean. Crate training is also useful when you need to board your dog or keep it safe while traveling.
Shih Tzu are often considered difficult to housebreak. The most critical thing is to avoid giving your puppy opportunities to have accidents inside, and to praise him profusely whenever he elimates where you want him to, be it on newspaper or "piddle pads", in his puppy-proofed area or outside. This means that your puppy should be constantly supervised inside the house until he has not eliminated indoors for at least four to eight weeks. You must also go with him, so that you can praise him when he eliminates outdoors. Watch for signals, such as sniffing and circling, and be sure to take him out every few hours, especially when he first wakes up, immediately after eating and after playtime. Suddenly, the light will dawn! A puppy has a very short attention span, so punishing him after the fact is useless and may instead teach your dog not to eliminate in your presence. You can gradually extend the time between outings as the puppy has greater control over his bladder. Some Shih Tzu owners teach their dogs to eliminate on paper indoors as well as outdoor all their lives, so they don't need to walk them in bad weather or rush home to let them out. You may want to associate a command such as "hurry up" or "go potty" with the act of elimination; this is useful later when you want the puppy to eliminate quickly in an unfamiliar place. If you are housebreaking an older dog, you may want to use piddle pants or (for males) a belly band with a sanitary napkin inside when the dog is inside, being sure to remove it and take the dog outside on a regular basis. After a few accidents, the dog will decide to go outside rather than be wet and uncomfortable. A classic book on housetraining is Shirlee Kalstone's How To Housebreak Your Dog in Seven Days.
