From my experience, Pomeranians are pretty strong-willed. It's important to be patient above everything else. Stay firm when giving commands and you should be able to train them the basics in no time.
From the most beginning you should practice the dog to live in the dark place also without fear. Sugar and salt contents in the food must be in very small quantity. Don't allow the dog to take more advantage from that owner. Daily practices must be wanted to train the dog.
Always reward your puppy for good behavior. Don't teach multiple things at once. Have them master one command at a time. Once he does something right stop for the day.
there are trainers, they are the right people to train a pet, specially the pomeranians. once when they are trained they are the best pets to be loved and to love.