Cathy's Corner has some excellent resources to help you with your writing.
If you are a newbie or thinking about becoming a mystery shopper, and need help with getting started, check out Shopper's Corner at Sonya's Mystery Shoppers. There is a self training section that all newbies should find very helpful.
Please explore the MSPA web site for information about their organization, and Silver and Gold Certification programs. I highly recommend becoming certified if you are serious about mystery shopping. I am so glad I decided to become certified. Since I became certified, I have see quite an increase in my shopping assignments.
This is a link to a cool online thesaurus.
Need advice about a shop? Get all the help you need from veteran shoppers at Volition.com, the 2002 award winning mystery shopping industry web site and support forum.