Bong, to be honest I screwed up on a few. I emailed them, they forgave. T
he best advise is 'practice makes perfect.' I know paying attention to detail is very, very important. I was a nurse for 33 years so that comes easily for me. I memorize every detail upon entering the door. Signs, prices, details about the people, glasses, that confounded bump on their nose!
Start slow, easy jobs. For God's sake do not do a McDonald's at first. There is detail, then there is perfect. That is Mcd's shop. If your memory isn't good, mystery shopping isn't for you. (a small scrap of paper for names is good as long as you are discrete) I have never been pegged a shopper unless it was a reveal shop. Even then they never knew until I told them.
Next tip: Always print out and read paperwork in advance! You cannot print and read on your way. I have found that most companies have the same policies at all times, but I read the new ones too, they do change often some monthly!
Some companies have you upload receipts, your CPI,(Contract) one seperate one for each job), and/or photos (digital of course). But job requirements for some companies are the same for the whole month, thus saving printouts to 1 monthly, the next month it may/maynot change.
Hope this helps!
Alice
Keep smilin'