I'm not an artist, and most certainly not a parent of artists, but reading all these suggestions brought one to mind.
In the book, "Zen and the Art of Motorcycle Maintenance", there is a description of a writing exercise given to a student who was suffering from writer's block. The assignment was to write something about the history of the town, I believe, and she couldn't think of anything. In the course of helping her find something to write, the teacher had her try writing about the college, to no avail, and eventually worked his way down through a particular buiilding on campus, to a particular wall, and finally to one brick in that wall. She came back with a paper written -- once she freed up her mind from all the things she was "expected" to write, all the things other people had already written that she couldn't match, and was able to focus on the subject of that one brick, which nobody had ever written anything about at all, the writing came to her.
I think I would have your daughter try painting or drawing some minuscule part of something like that -- something that she doesn't feel the pressure of copying the "expected" views of, and can just make something all her own. One petal of a flower, or the underside of a rock, or one square inch of the refrigerator door.
