P.J.
use a soft baby toothbrush w/ just a dab of toothpaste. She don't need much cause you want her to swollow as little as possible. She also don't need much cause to much floride can be bad for her. You basically are just getting her in the habit of taking care of her teeth. As she get older and more teeth come in and she learns how to spit out the toothpaste you will then give her more.
Hope this helps,
P.