Take the time to shift your thinking from perfection to learning the skills necessary. Being a mystery shopper is not unlike any other trade or job. You have to learn the ropes. Give yourself the time and space to do this.
There are a variety of mystery shops waiting for someone like you to complete them. If you are looking for an apartment or want to try a new restaurant, then mystery shopping is the way to go. Mystery shopping also allows for you to provide invaluable objective feedback to those who can actually make the changes. Therefore, if you are a customer service geek, like me, this makes the icing on the cake.
There are plenty of blogs written here to help you on your journey. And remember you can always ask questions. There are no silly questions just silly people who think that asking questions are silly.
The goal of the mystery shopping company is to complete a successful assessment for a company. It is in their best interest to ensure that you can do this. Just follow their lead and read anything that the company states that you read, no matter how simple.
I would also suggest always checking shop details the day of the shop completion as well as right when it is assigned to you. Why, you might be thinking? To make sure there were no last minute changes to the shop notes. Just trust the process. The mystery shopping company has trained many shoppers prior to you, they know what they are doing. When in doubt, e-mail a question to the staff.