Here's an example of one of those earlier answers that should be helpful to her, too:
http://www.collegeconfidential.com/dean/tips-for-getting-off-the-yale-waitlist
As your daughter launches her waitlist campaign, try to help her to get excited about the places that have already said yes. But if she is single-minded about attending this one, her best bet is to put on a full-court press, as described in the column above.
One final tip: I'm sure it's tough on your daughter to not receive the news she wanted from her first-choice school. But it's probably even tougher on YOU. As a parent myself, I know how hard it can be to see a child disappointed … especially one who seems to have done everything “right" to reach a goal. But, from years of experience, I can assure you that this crazy process often does end in a “meant to be" way. So even if your daughter never does get off that waitlist, she may discover that the school she DOES attend could feel like the place she was supposed to be all along.
Good luck!