Dictation practice to prepare for university.

I had a 3rd year high school student ask me today to help her practice dictation for her university entrance exam.  We'll be practicing for an hour 3 days a week.

I'm new at teaching EFL so I was wanting ideas on how to best help her practice. She's very motivated, so it's not an issue of keeping her interested, but I'd still like it to be fun for the practice to be as effective as possible.

Thanks.

Hey
It can be difficult esp with 3rd graders.  I make my own dictation and I make sure that the people speaking have different accents.  The kids are not generally used to it so it gives them practice that they wouldn't get otherwise. I use the Planet Earth series quite a bit, a BBC doc Out Of Africa, and just random other things. Next week I am doing one on Chernobyl.