on top of what everyone else has said, another thing that will go a long way in potty training is to make sure the accidents in the house are properly cleaned up, especially if you have carpeted floors. just because you can't smell urine doesn't mean your dog can't, and she will continue to go in places that smell like potty. Here's the method that works for me - it's time and money consuming but it helped me make a lot of progress in potty training my dog. (i'll include links for all the products i mentioned, in case you're curious)
I purchased a blacklight urine detector from petsmart to find the little pee areas that I missed - get the room as dim as possible and turn your blacklight on. Pee stains will glow white under the blacklight. If you turn it on and discover that your carpet is totally littered with white glowing stains (like what happened to me when I first used it - yikes), consider getting your carpet professionally cleaned and pet treated to start over, if you can afford it. I paid 80 dollars when I had mine done.
Once the pee stains are located, soak the area with a cleaner that has an enzyme urine destroyer in it. Nature's Miracle is a pretty popular one. (if it's a fresh accident blot up as much as you can before this step) let it soak in for 5-10 minutes, then clean the area with a carpet cleaner. I bought a compact carpet cleaner from petsmart specifically for accidents, but if you already have a carpet shampooer or something similar then that should work just fine. After that, I spray the area with something called No Go, a potty training aid. I absolutely love this stuff and I swear by it. When miles has to go potty after I've sprayed this stuff on the carpet, I'll see him sniffing around frantically with his nose to the ground looking for a spot that doesn't smell like the no go - another thing that helped a great deal with potty training, since i could easily spot when he was looking for a place to go.
If you don't have carpeted floors, obviously accidents are much easier to clean up.. just make sure you aren't using a cleaner that has ammonia in it, as ammonia smells like urine to dogs.
I hope my post was at least somewhat helpful.. good luck with your potty training. I know that it can be stressful.. just know that while yorkies are notoriously hard to potty train, they are also very smart. They will learn what is expected of them if you are diligent enough.
Simple Solution Spot Spotter - New Puppy Center - Dog - PetSmart Nature's Miracle® Stain & Odor Remover - Natures Miracle - Featured Products - PetSmart Pawsitively Clean™ by Bissell® Yikes! Compact Deep Cleaner - Cleanup, Stain & Odor - Cat - PetSmart Top Paw™ No Go Training Aid - House Training - Dog - PetSmart