Act Like a Private Detective
In some respects, being a mystery shopper is a little bit like being a private detective. Your goal is detect the level of customer service at a particular retail establishment privately. In other words, you need to be careful that you are not detected yourself by cashiers, sales staff or the managers on duty at the time you are conducting your mystery shop of the store. Sometimes this can be a bit tricky. For instance, one time I tried to compete a mystery shop at a very small college bookstore. There were 3 sales staff on duty and I was the only shopper. I would have had to rather suspiciously walk around the store recording various types of information about some college textbooks in stock. When I attempted to make my rounds, I was followed around by one of the sales staff. I don't think she was suspicious at the time. She was just bored and being friendly, but I'm pretty sure that if I'd stopped to write down some information about a Nursing textbook and then an Accounting textbook she might have gotten the idea I wasn't just a regular shopper, especially if I'd walked out of the store after only buying a stick of gum and requesting the receipt!
In that particular instance, there was just no way around it. I didn't complete the mystery shop. Instead I called into the office to report that I wasn't able to successfully conduct the shop without being detected and we rescheduled it for another day.
Why didn't I just go ahead and complete the shop with the shop associate following me around the store?
If I'd done so, it is highly likely that she would have been able to easily identify me as the mystery shopper when the store read my report about my shopping experience and if she had, not only wouldn't the company that was contracted to complete the mystery shop get paid for their services, but neither would I. It sort of defeats the purpose of mystery shopping -- which is to see how employees treat regular shoppers -- if they figure out that you are the mystery shopper and therefore provide better customer service than they would to their regular shoppers.
So before you become a mystery shopper make sure you sharpen your skills at sneaking around and blending into the woodwork everywhere you go. You want to be the everyman or everywoman without too much attention being paid to you. If you're already great at blending into your environment, you already have the most important skill required to be a successful mystery shopper.