Does she run on the balls of her feet when she does the high knee running drill? If she does, I would set up a couple hurdles low and close and tell her to do high knees to and through the hurdle. Doing high knees over a hurdle really gives the athlete the feeling that hurdling is just another running stride.
Sometimes leaning more over the hurdle will help the athlete land on the balls of their feet as well.
I could probably give you a few more ideas, but that is where I would start.