Also, proof of work when possible.

For instance, if she's applying for a UI development job, she could (gracefully, without appearing critical) find a webpage on their site that is hard to navigate. Then she could create a few alternative web pages, and explain what she did, why it might be improved, and how it could be tested.

Proof of work is not always easy, but is insanely valuable when possible. I wrote some magazine article a while back, with some "how to" details on my technical specialty. I would always bring the magazines in (printed, so it was a while back) to job interviews. They were like magic.