Probably the most thorough retail interview process I've ever been a part of. It started with a phone interview that lasted 20 minutes, and then three in-person interviews with different supervisors and managers. I spoke with about six people total, and received a job offer an hour after leaving the last interview.
Everyone I talked to was kind and unpretentious, but let me know that they were very picky about who they hire. This was for the highest volume store in a major city, so this might vary by market. I answered the same questions to several different people, which was slightly annoying. Be upbeat, make them laugh, and don't make it seem like you're there just because you need any job you can get. They're big about work-life balance, but they want to hire employees who are enthusiastic about the company.
Dress code is casual. I started off with a blouse and dress pants, second interview I wore a sweater and khakis, third time around I wore an oversized sweater and leggings. They don't care about your appearance as long as you don't look like a complete mess.