^^^ I absolutely concur.
Can't stress enough making a big deal out of the potty. Even if you say "good potty" 15 times all happy over and over again while s/he goes. Always Praise the potty!
If s/he is 1, s/he should be on a pretty regular potty schedule. For instance, Rosie only goes poo once a day, in the morning. Amelia on the other hand, will go 2 times - in the morning and in the afternoon. Try to make note of when s/he does what & stay out with your Yorkie until s/he does it. Make no sound - ignore her (him?) until s/he goes. When your Yorkie does, praise the potty!! Between consistency in your going out times & praising the potty, s/he should get it.