If you have already been into the practical part of the craft, there are some things which could help boost your chances:
I think the term is self explanatory. Use glamour magic to make yourself more attractive, pleasant and so on
Cons: Say that you make yourself look better than you already are and you are actually hired, are you ready to work hard to prove that you really are worthy keeping?
Clear your mind, rid yourself of anxiety, believe in yourself, trust yourself, you can do it!
Meditate on those goals everyday till Friday. Take a deep breath on that day and go get that job!
Cons: If you are not already familiar with meditation, the chances are high that you will fall asleep on the proccess
Stand in front of the mirror and 'practice' the interview with yourself, that will help you feel more confident.
Do breath control exercises every day, will boost your confidence and lower your anxiety.
Having done all the above, be yourself, act naturaly and don't push yourself. Trying to be something you are not will not work out well. Show them that you can do it but first, believe that you can do it.