I think that work experience and personality are the most important qualities to impress an interviewer. Sometimes a god personality can overrule the appearance. If you have good character, you can achieve so many things in your work. The work experience gives you a solid background and confidence that are necessary to face a professional career.
I have been in some job interviews. Some were good and others weren´t. Some interviewers ask you personal questions that can make you feel uncomfortable and I hate when that happens. But you can learn something with all job interviews, in order to be better prepared to the next one. The important thing is never to fell defeated.
In your first interview you have to stay as calm as possible. Put some comfortable and sober clothes. Be punctual and give straight e clear answers.