I had the same question. I ended up going in my school uniform. (Nice dark blue pants, black boots, and a button up white shirt with a school patch) I got my NREMT earlier this month...brand new baby EMT. B) Do you guys any advice on some keywords that EMS companies want to hear with new EMT's?
We want to hear that you know this is a job, not a mandate from god. We want to hear you will show up for work on time, not that you are "so happy to be doing good" for your fellow man. We want to hear you ask about shifts, opportunities for advancement, and what sort of community events does the agency participate in, not about how soon do you start accruing vacation time.
Know a little bit about the agency where you are applying. Don't mention how you almost got hired somewhere else but the interviewer was a jerk. Don't bad mouth other agencies, former employers, former co-workers.
Act like a grownup, dress like a professional and treat the interviewer with respect. Show up early, leave when you are supposed to and thank them for their time. Remember you are one of maybe 7 or 8 contestants for the job and the interviewers job is to find a reason to eliminate the 6 or 7 they don't need. Don't give them a reason for one of them to be you. Don't giggle, curse, chew gum or bite your fingernails during the interview. Look them in the eye when you talk to them and think before you speak.
Let the silences be silences, don't fill up every gap in the interview with useless chatter. Be honest, be forthright. It's okay to ask them when you can expect to hear from them and will they notify those not hired. Have a few pertinent questions about the job or agency that show you truly understand that this is work. Ask for a tour of the station, offer to come back at a more convenient time if they can't show you around now. Ask how long people stay with their agency. An agency with a high turnover is a warning light, either crappy working conditions, low pay or sloppy admin. Remember you are there to determine if this job is right for you as well as they are to see if you are right for the job.
Good luck! Come back and let us know how it went.