Hi There,
Firstly, well done on securing an interview. Your CV and covering letter must have really impressed the hiring team! The first thing to remember with an interview is that it’s just that- and interview. It’s not an interrogation and I personally find it easiest to get through an interview by pretending to myself that I already have the job, and that helps you to relax and answer questions more calmly.
With a high street store they are going to be looking for someone who is capable of serving the public in a friendly and helpful manner, whilst looking smart and presentable. A combination of a smart skirt or trousers, with a smart shirt or fashion top would look smart.
Usually in these types of interviews you will be expected to answer a range of questions about working in customer facing environments and assisting customers, as well as answering questions about any previous similar roles you have undertaken, so think in advance of examples you can give of good service given or how you have relatable experience.
Just remember to keep calm in the interview and listen to what you are being asked. Be honest, and if you are struggling, don’t be afraid to ask for a few minutes to think. Research the company so that you know all about them, and be sure to have some questions of your own lined up to ask your interviewer, and remember, if you don’t get the job don’t see it as rejection- you wouldn’t want a job that wasn’t suited to you, so it’s important to be honest.
Good luck!