How should you prepare for an interview at UNIQLO Retail Stores?

Have a general background on what UNIQLO is, emphasize how well you can work in a fast paced environment & how much you can tolerant mean customers

Prepare as you would for any other interview, and don't worry or overthink it. They aren't looking for the best of the best, they simply want someone who they can trust to get the job done. So just be yourself and sound confident when you speak; confident tone can do wonders in an interview. Lastly, wear a casual and simple outfit as if you already work there (even better if you wear UNIQLO itself). Small things like this will make it easier for them to picture you working in the store as opposed to someone who comes fully covered in Nike.