Thank you thank you thank you!!! I have the same stuttering problem, so I'll be trying that one for sure!I haven't had my congressional interview yet, but I have been in plenty of professional interviews. I have learned a number of things.
1) Be honest. Honesty is crucial and try not to produce canned answers that you think they will like to hear.
2) Be yourself. I'm a bit funny and I enjoy talking to people. During my ALO evaluator interview for USAFA, I was professional but also showed the humourous side of me. My evaluator and I had great discussions. Because I was being myself, I felt more comfortable, prepared, and at ease. Being yourself also provides a true look at who you are to the interview panel. Not just what it says on paper.
3) Answer questions with experiences. This is something that has helped me out on so many interviews. Try your best to answer the questions they ask you with a story or an experience that you have been through. This, however, does have it's limitations because you can't provide a story for EVERY question that they ask. Regardless, it is good just to keep this in mind. Sometimes you can answer multiple questions they may have just by telling a few stories.
4) Cool. Calm. Collected. It can be easy to become nervous before any interview. Especially when your acceptance to a SA depends on it. But be calm. I have a stutter problem because my brain processes things fast and when I try to speak, a huge mess comes out. What I have learned (and it has helped me tremendously) is to be calm and think about your statements before you speak. It helps get rid of my stutter and allows me to sound more professional and polished. I know it sounds silly, but I would recommend to try it every time you speak or interact with someone. Think about exactly what you are going to say before you speak, and once you have done that, then speak.
5) Engage the panelists. If multiple people are doing the interview, engage them all. Eye contact is crucial but interact and talk to all of them. If your interview is virtual it may be different, but respect and acknowledge the presence of everyone on the panel.
6) Look through the forums. There are a lot of other tips I haven't mentioned that are hidden on this forum. I would encourage you to look for tips, but also practice them.
Your composure is key. Being nervous is a natural feeling but if you can overcome it, that is what can set you apart. At the end of the day, you have a job to do. You want to attend a United States Military Academy and this interview is just one part of that job. Treat it as such. Be respectful, responsible, and diligent.
Good luck and I hope this helps.