Why does my Shih Tzu not eat her food?

Stick with one food.If you want to mix it up with can food do half dry,half can food. with minimal people food broken into small pieces then mix.Do not give anything else til she eats her own food.Leave it out for x minutes then pick it up.If you dog just eats the can food and the people food give the dog the remainings over the next couple days,When she's hungry she will eat.Do not leave dry food mixed with can food in the refrigerator more than 3 days straight,By the third night toss it and make a new batch