Well since both my filly and I are new to this I figured I should go easy. I've watched quite a few videos on it, and I know I'm doing it correctly...its just taking a while. I don't want her to get too opposed it.
What you can do is stop occasionally and give her a good crest rub...really massage it. It relaxes them in between. I do this to mine even if they are already calm and quiet sort of as a reward for staying that way :)