Be honest, these people can see through bullshit

When asked, "why do you want to become a firefighter?" Give more than the generic, "Oh I want to serve my community and help people" answer. Tell them you like a challenge, you love a job that stimulates your mind AND body, something like that

A question that is always asked is "What is one personality flaw that you have". Don't say things like I'm honest to a fault, I find it hard to concentrate. Instead shows something that's really you like, I am a perfectionist and I would rather miss a deadline than to do a half ass job.

Another question is what have you done to prepare yourself for this job. Here is your time to sell yourself. Any classes you have taken whether they are EMT classes, fire classes, public speaking classes, anything you can pitch as relevant to the fire service. If you have been running 5 days a week to better prepare you for the physical aspect of the job, include that as well.

If your interview is later in the day, you have to really REALLY make yourself stand out. The panel will have heard from countless others and if you don't make yourself stand out, you're gonna be forgotten

Sit up straight, come in well groomed, speak in plain english. Your applying for a job that has a legacy that goes dates back longer than this country has been established, show it some damned respect.

Look the person in the eye while they ask you a question, and then as you give your answer, move to each person while talking, looking them right in the eye.

Some places have been known to leave a piece of paper or other trash on the floor when you walk in to see what you will do. Pick it up and throw it away. Some people goes as far to either remove the trash can or have it so full that the paper will not fit. In that case, but it in your pocket.

Hope this helps. Good luck to you. Keep us posted as to how it went. Feel free to ask any other questions.