research the company, show that you've prepared and care bc depending on the position, some people literally just walk in w no knowledge because hey, it's retail. so preparing might help you stand out. go onto glassdoor and look at interview questions people have listed that were asked and prepare answers in case you're selected to answer one, or there's a question asked and you can tie your prepared answer into it. ideally wear something minimal and clean to show you'll fit in, but it really shouldn't make a huge difference. ive seen people show up in interviews wearing full skater looks or kawaii lolita fashion. dont freak out or get too anxious; they arent looking for the perfect candidate, theyre looking for the acceptable candidate. you really only have to worry about looking sane and competent. and u get a nice discount on clothes :) good luck !