A strategy that I found works wonders: don't give a damn about the interview. Go in looking nice and presentable and whatnot, but think to yourself "I'de be doing them a favour taking this job, I can find a job anywhere" because honestly, you can if you put your mind to it. Of course, don't be rude or show any attitude, do your research etc.
This will not only will give the impression that you are in demand, but not looking nervous will really go the extra mile for you. It makes you look like you have a lot of experience in this kind of job/situation. It's never failed me and even gotten me a job I was totally unqualified for, turning up to an interview completely underdressed. I absolutely aced all the questions as I just stayed so calm.