Recently I was denied Visa by the German Consulate in Lagos, a decision that almost broke me. The truth of the matter is that I would have been served better if I had prepared for the Visa Interview. My documents were in a good place but I lacked knowledge of the country I was applying Visa to. That was the first time I actually felt the impact of not preparing for something.
Hither to, I would go into something unprepared and push my way through. I am not saying it had been easy in all my trials but this particular visa instance was an easy one that would have worked if I had prepared for the interview.
A few months later, I signed up for a language class. The last part of the exam required being in an interview with examiners to examine how well you can speak the language. I did simulation twice before the exam. The first one brought out a tensed me and fumbling with the answers I already knew. After the second trial, I was so confident that on the exam day, I literally went through the interview like it was my everyday duty. That was the first time I had gone through any interview and come out like I owned the panelist. Yes, that was also the first time I prepared for an interview/exam. Coincidence? Try it!!!
Admittedly, to prepare well is a skill which is more important than many others in an interview. SPEND TIME RESEARCHING WHAT YOU ARE ENGAGED IN. After that simulate the process and feel like you own the process. That will show the interviewer that there is at least some interest in the subject.
By being well prepared you will be less likely to give poor answers to questions or babble on and on.