Rachel answers an age-old grammar question about was and were. Old grammar rules stick in our minds like chewing gum in the hair. The rule you remember is no longer a rule (perhaps it never was) but a choice. Rachel tends to use ‘were’ out of habit, but 'was' is now more than acceptable—it’s the norm.
Editing is always a step-by-step process. And always you start by asking the big questions, such as: