Hi AriaJolie,
I assume your an international student. I am too and had my interview over the phone.
When the phone rings and you sound nervous, just tell them that your application is very important to you thats why your nervous. That will appreciate that.
Be prepared and have answers to questions like why do you want to do a PhD? what was the hardest part of your MSc thesis? how was your supervisor? do you have the skills to do a phd etc?
MH