You've left your run a little late, but here are my tips:
do your research; employers love to quiz you about what you know about their company, so the more you know the better.
Make sure you are familiar with the location; I often go for a "test run" when going somewhere new that I have to meet someone at, especially for interviews, or appointments. That way you will know where it is, how to get there, how long it takes, and feel a bit more confident.
You haven't said what kind of retail store; is it just a job, or a store selling something you are really interested in?
The more interest you have in the products you will be selling the better you will go; you don't have to be an expert, and you don't need to know everything, but if you are lacking in knowledge, you need to make up for it in enthusiasm.
If you are keen on books you should not be selling toys or DVDs etc and vice versa; however if it is a department store, you can say you are willing to work wherever they put you and would be happy to work towards being in an area of your special interest if given the opportunity.
So far as staying calm during the interview, if you find yourself tense concentrate on your breathing, if you take a count of three to breathe in and then three to breathe out, you should slow down your heart rate and return to a calm state after a couple of minutes.
If you sweat, make sure you use a deodorant, and wear a jacket so you don't drip or feel too self conscious.
Don't worry too much about facial expressions or whatever, just be yourself, answer the questions, and show interest and enthusiasm, don't be afraid to show some humour too, provided it's appropriate and not adult humour!
I also find to avoid the eye contact anxiety response, my best technique is to look at the nose, the eyebrows, the lips the face, the hair or whatever, but don't spend too long holding the gaze, as you will get anxious.
NT's are fine with you looking at them but not in their eyes, but will think you look shifty if you keep looking away from them too much, or look down or sideways.
Other than that, consider why you're going to the interview; it's an opportunity to have a job working in a store selling retail products; if this is what you want to do, that should be enough to help you feel enthusiastic.
Don't mention the Aspie thing, but it could be beneficial if you mention your Aspie character traits that can be seen as strengths; attention to detail, desire for things to be in order, good memory for stock items, names, faces, or whatever your particular strengths are.
You won't come across as angry or bored if you imagine yourself in the position while you're at the interview, so use that if you feel you're not looking happy or enthusiastic enough.
If its' meant to be it's meant to be; just do what you can, and let what happens happen, but remember it's just a process, and the job is the goal, getting though the interview is just as much a nervous and difficult process for the interviewer as it is for you, so don't feel scared; the interviewer may be more frightened than you, just better at hiding it!
08 Jul 2013, 5:02 pm
I went there, but at the last moment started to panic a lot and left. I think I have bad self esteem problems because the whole way there I was worrying and thinking I'm not good enough for this job 
