Read and reread the instructions. Each shop will have its own unique set of questions. You may be required to ask about something specific or remember what is listed on a sign in the entry way.
A shipping shop will go really quick, you need to be timing and thinking about all you need to remember.
For many shops, the restrooms and fitting rooms can be your best friends. Go in there and review the sheets and take notes on what you have learned so far.
I will tell you there were many times where I "misplaced my cell phone" early on in MSing, so I could go in and look for one more thing after leaving.