Well to begin with a young Yorkie tends to have that very natural look.
Sometimes as their hair is growing out you kind of wonder what they are going to end up looking like!
First make sure you have the right grooming tools. You want a couple of sizes of a decent quality metal grooming combs. I use a 4" for the face and legs and a 6" for the body.
toplinepet.com Here are some good examples of good combs. I also have the small pin brush but I never brush until all tangles have been combed out.
With a puppy it is best to start when they have been napping. Take your small comb and run it through the hair a few times. Play time is not the best time to decide to do the grooming and, yes, I know they like to play most of the time! Right now the hair is not as long so it is easier to get the comb through the hair quickly and painlessly. Do it at least twice a day so that when the day comes when her hair is actually long and needs lots of grooming she is already used to the routine.
Giving a healthy, tasty treat directly after the session will help a lot with her attitude toward grooming.Always give lots of praise. Never punish an active pup. Do what you can and then try again later.
I would suggest finding a good quality all natural shampoo and conditioner. It can make a world of difference in how manageable her hair is between baths. I use the YSS products including the spray conditioner.
Yorkie Splash and Yorkie Shine | Yorkie Shampoo and Yorkie Conditioner
I also have used WEN on her and it works great as well.
A weekly bath will also help in her training and keep her hair easy to comb.
Training a pup to accept grooming is just like any other behavior you train for. It takes lots of patience, love and encouragement as well as being very consistent with the plan.