Your Shih Tzu will need quiet and short training sessions with you in order to train even easy tricks. Make these sessions free of distractions and keep them short so you can keep the focus and attention of your fuzzball. Do not forget about the highly rewarding treats to entice and encourage him to continue learning. If you need to keep your little guy focused and workout in one place, you can put him on a leash to get better control over him or her.
Source: 2cute2shihtzu