"....anything special we should know?"
Only about a hundred different things!!!! Tough time to be learning as she is having the puppies though. Hopefully you have read at least some basic whelping info. If not, pls start between pups. I am still awake, if you have problems, feel free to call me. I'll PM the number.
Main thing is to make sure she is able to have each one easily and doesn't go more than an hour between puppies. If over an hour and it appears there are still pups inside, then you probably need to take her to the Emergency Vet, along with the pups she has had. Keep everyone warm. A heating pad underneath a plastic box (like an underbed Rubbermade container) will do fine. Make sure the entire area is NOT covered by the heating pad. That way if they need to get away from the heat source, they have room to do that. Overheating leads to dehydration quickly. Has she been chewing through the cords herself or are you cutting them? If you cut the cord, tie thread in two places an inch apart & cut between.
When she is done having the puppies, make sure she gets the afterbirth out. There is quite a bit of it. If it does not come out on its own, she needs to go to the vet. I would suggest taking her to the vet when she is all done no matter what. If all is going well, it can wait til your regular vet is open. But I would have him check to make sure all is out and maybe even have him give her the after shot to help as well as examining to check for possible tears. I think I might have been able to save my girl, if I had done this. If an infection develops it can be deadly so very quick. So stay on top of momma and how she is feeling. Here are some sites that can help you out. The first one is my fav.
This is probably one of the best online sites for info:
Canine Reproduction Video and Book on Breeding and Whelping dogs by Debbie Jensen for dog breeders and Whelping trouble.
Here are some others to read too.
Whelping - Yorkshire Terrier Having Puppies Jon-An's Yorkshire Terriers (Puppy birth) List of things needed to whelp puppies YorkieInfoCenter | Yorkshire Terrier Puppy Care | Newborn