What should I wear for A interview If I a looking for a Maintenance or Stocking Job?

Dress pants and shirt.

I think a nice polo shirt and some khakis would be appropriate. It's not overly formal, but still nice enough that your employer will know you're taking the interview seriously.

Try not to dress "trendy." A nice polo shirt doesn't mean an Aeropostale shirt with the company logo and other text emblazoned all over it. A small logo on the chest is okay; a giant "established 1957" across the front is not. You probably already knew that, but I'm amazed at what people will wear to an interview.

Get rid of any unnecessary jewelry. A watch is fine, and a wedding ring is appropriate if you have one. Make sure your face is cleanly shaved, and your hair is neat and recently cut. Wear light cologne (1 or 2 sprays) or no cologne.

That should cover it as far as appearance. In the interview, try to be professional, but don't be a robot. Smile, use some body language, and above all, be relaxed. It's normal to be nervous, and it's okay (possibly even beneficial) if your interviewer picks up on this--it means you're taking it seriously. Nobody wants to hire someone who's stiff and has no personality.

Try to make the interview a two-way conversation. Most interviewers will be as uncomfortable as you are. It helps a lot to establish a rapport. If you have questions, ask them. Questions about advancement opportunities and business routines can help shift the interview away from a strict script and allow the interviewer to dispense some personal knowledge and opinions. It can also help the interviewer see you as an individual, and not just one of many applicants.