Interviews can make people behave differently. When under pressure and in stressful situations some people talk too much, give out too much information, talking over the interviewer, not listening to the questions in their entirety, and quite simply can talk themselves out of a job. Then there are people who appear very laid-back and seem to lack enthusiasm for the role, when underneath they’re extremely nervous – their nerves make them retreat into their shell and struggle to find the response the interviewer is looking for.
In an interview situation, you need to be very aware of your personality traits. If you know you have a habit of talking too much – pace yourself. Listen to the questions you're being asked in full. Give yourself a moment to think about your response. If you're at the other end of the scale and you know you have difficulty in expressing emotion in difficult situations, make a point of actually saying to the interviewer that you’re very excited about the role and that you feel you are right for the position, and give your reasons. Don't let your nerves get the better of you. Your CV has got you this far. Well done. The next bit is up to you. Know your strengths and weaknesses, and don't let old habits get the better of you.