The first thing you should do when the candidate arrives is to make sure they are comfortable, seat them and introduce everyone in the room. Explain to them that you will be noting down their responses so are not ignoring them if looking down, and that this is their opportunity – so just ask if they want anything repeating or explaining.
It’s worth letting them know roughly how long the interview will take, and how many questions you will be asking so they can mentally prepare. As an opening gambit, it is usually best to ask them to “tell me about yourself and why you applied for this role” – this allows nervous candidates to get everything off their chest which they want to say to you, so they can then focus on delivering the answers to your ‘real’ questions.
Within the interview, you should try to keep the candidate at ease, by breaking down long questions into smaller chunks, and using “active listening” skills – periodically make eye contact, nod, or make affirmative noises so they understand you are listening – but make sure they do most of the talking.
It is important to record what the interviewee says in response to your questions in order to compare the candidates later. You do not need to record their responses verbatim, but make sure you capture sufficient bullet points to remind you of their answers, and highlight any particularly good (or bad) points. Remember that you may have to disclose your notes, so make sure anything you write is fair, proportionate and not libellous!