I've found most plot holes in my manuscript involve minor characters. Because I'm so focused on my main character, I often forget things such as if a minor character has access to a car, is on a diet, or is angry with someone. One easy way to check for holes: in Word I can go to Edit--> Find, type in a character's name, and click in the box "Highlight all items found". Unfortunately, if I then click elsewhere in the document, this highlighting will disappear. To make it permanent I can highlight the text in a specific color using my toolbar. This makes it easy to skim through my text and focus only on a specific character and make sure her voice and actions are consistent. You could do this for all your characters and make each name a different color. When you are finished with your character revisions you can go to Edit--> Select All and change the highlighting to "None".
The highlight feature in Word is turning out to be a rather handy feature for writers! I think we've seen two or three other tips on how to use it in different ways. Thanks so much for this one, Anne! Very helpful.