I've been grooming my yorkies myself for about four years and I really enjoy the whole process. They know what to expect and they are easy to handle. They get the biggest treat afterwards
At first, when I tried to trim Cash (my oldest), I made a lot of mistakes by trimming him too short. But it grew out and I learned
I also have a small girl, June. Unfortunately, she has a cotton coat and my efforts to grow her coat went down the drain. I cut her down last week and she looks like a puppy again.
To groom your girl, trim her ears first. Take it slow and keep reassuring her. If she isn't comfortable with the scissors near her ears, get her used to them first. Cut the ears cleanly around the edges. It helps to have a source of light to see the ear through the hair, although with your baby's thinner hair, you may see it easily.
You can trim the backs of the ears into a V shape. Cut her nails with a special nail clipper. You can read up more and watch some Youtube videos to help you.
To trim her body hair, get a good hair scissor and comb. Comb her wet hair (you can use a spray bottle with detangler) and find a length you like. Rather keep it long and trim again than cut off too much.
Once you've found a length you like, you just keep cutting all her hair to that length. Move from the spot you started and work in sections. It takes a while to cut them (as opposed to shaving), but I prefer their hair a little longer.
I really hope that helps. I'm attaching a cellphone picture of both of my yorkies - they were trimmed last week and bathed and photographed yesterday.