Hi, Abba!
It would be useful if you present your students a pp with some guidelines including simple and clear questions/answers.It�s nice to introduce a few important topics....
Try to use funny images in the powerpoint to motivate the students!
Some questions they might use to practice role plays(one being the interviewer and the other one the vacation applicant):
-Why did you apply for this vacancy?
-Which are your wage expectations?
-Which do you consider to be your best qualities?And your defaults?
-Do you have a full clean driving license?
-Tell me about your work experience.
-Do you have any question you would like to ask about the company?
Hope this helps...Have a nice day!Hugs from Portugal!