The best tip to help you ace and interview and control your nerves is to BE PREPARED!!! By doing a little bit of research and planning out what your answers would be to some generic interview questions you can really give yourself the upper hand.
Some really useful information about preparing for an interview can be found on the national careers service website. This page outlines the top 10 types of questions employers will ask you and also gives some advice on how to answer them.
https://nationalcareersservice.direct.gov.uk/advice/getajob/interviews/Pages/default.aspx
More information can be found on the My World of Work website:
https://www.myworldofwork.co.uk/getting-job/interviews