I've learned that Yorkies are very smart and finicky dogs. Teaka is my first Yorkie and I've learned a lot. However, training her wasn't any better or worse than any other dog I've had. It just took longer.
::FYI, if you live in a climate where it rains or snows for lengthy periods of time, get yourself potty pads as back-up. They have saved many a rug stains in my house. Oh and don't have green rugs! Teaka thought it was grass.

Shes so smart!::
I first got Teaka in April. She was 8 weeks old, and this tiny lil thing. I didn't feel safe with her wandering around the house. She looked like an overgrown gerbil. She was so tiny!!! So I had this playpen set up for her in the livingroom. It was rather large, so one corner had a potty pad, on the other side, opposite corner was her food and the rest was well a play area.
I would feed her, and then wait 20 minutes. I would actually pick her up, and place her on the potty pad and say "Go pee pee" Sometime she would just look at me. I found it better for Teaka if I didn't look at her, but I stood right there. Sometimes I'd pick her up and place her there again. I would wait 5 minutes standing there, then I would decide she probably doesn't have to go. She has always been on a feeding schedule, and I would purposely feed her an hour before I had to go anywhere so I made sure she went. If she did use the potty pad there was always a high pitched "Good Girl!!" and a treat of course.
Eventually she outgrew the play pen and we moved the potty pad to a discrete location in my house. Again I showed her where it was and placed her there on several occasions. Once she learned to use the potty pad, we slowly moved the potty pad across the house (yes in plain view of guests) towards the slider door. She kept on using it, and then we actually staked the potty pad outside. (Thankfully this was in the summer when it didn't rain all that much) She kept on using it. Finally we got rid of it.
Then we had the issue of, well how the heck do we know when she has to pee? She started having accidents because we weren't seeing the signs. So, I attached a round bell (think jingle bells) onto a string and attached that to the slider door handle. She would look outside and I would say "Have to go Pee Pee?" she would look at me and I would ring the bell. Then let her out. I did this for a couple of months I think. She would ring the bell. Then I'm like, well that bell is kind of stupid looking. Then I taught her to bark on command. So when she would ring the bell I'd say "Teaka speak" and she would.
Now 3 years later, Teaka will sit at the slider, scratch it, or bark when she has to go outside.
She will only have accidents if no one is home for more than 8 hours (but she'll use the pee pads) if its snowing, or if its raining, or if shes sick (pooping issues). Other than that, I'd say she goes outside about 93% of the time.
We always have a pee pad out for Teaka (where guests can't see). If I see her starting to circle on it, I immediately get up and put her outside. She knows the pee pads are for emergencys only.
Keep at it, it took months for Teaka. I think she was about 6 months old by the time my whole process was done. Teaka is not crated at all, for a little dog, she does really really well.