Your voice will telecast uncertainly by cracking or with an inappropriately casual “you know.” Do not use levity or say, “yada, yada, yada” while practicing, for under pressure, this could be what flies out. Be sure you do not use any inflammatory words or words that could be misinterpreted, and keep within proper conversational perimeters. You are not there to create controversy, shock, or perform stand-up comedy. You are there to sell yourself to this panel and show that you are prepared for this job.
On the other hand, don’t get too uptight. the panel is not there to wash you out. This is a control pressure but not adversarial. It is often a predictor of how you think on your feet and how you verbalize under pressure.
Practice
Practice by several methods. Have a trusted friend ask you the questions while you respond to them verbally. It is important that you can get the words, statements, or phrases out of your mouth. Practice known responses while driving.
The opening question such as ‘tell the panel about yourself”. The brief biographical response is your opportunity to tell them about yourself. You know the answer, they do not. If anyone knows about why you are prepared for this job, it is you! A pointer here: If they have certain requirements such as education, tell them what you possess. Do not make them review your packet to see if you meet the requirements.