Try to relax and control your breathing that way your thinking brain will be at its very best! Also visualise having the job and how exciting that will be if you believe the job is the right one for you and YOU are the best person for it then it will be easier for the interviewer to believe it too. Sending you good luck vibes
Just got home, and I have no idea how it went really. After 2 hours of interview I was fed up of talking. Thanks everyone for the messages, I really appreciate them and I had a quick read before the interview. I'll start a new thread "I got a new job" if I get it, if not - don't ask )