|Courtesy of penywise|
Like any other of the various rules, these things are meant to be helpful, but should be taken worth a grain of salt. While they are good things to keep in mind in general, they don't apply to *all* situations.
Tenses, for example.
The use of helping verbs--the dreaded had--or 'to be' verbs, when dealing with tense, are necessary. (And here is where I'd caution that writers pay special attention to the tense they're using. If a writer finds themselves mostly in the past perfect tense, it might be a good idea to re-evaluate the structure of the story.)
Most people know the three different tenses by name: past, present, future, but there are subgroups for each. It's a good idea to be aware of these, especially in terms of how a writer is using them in their manuscripts and for their story structure.
Past Tense--the tense in which things have already happened.
Simple Past: I wrote a book.
Past Progressive: I was writing a book.
Past Perfect: I had written a book.
Why is it so important to be able to distinguish between the three subgroups above? For me, it's a matter of temporal accuracy. Most novels are written in the past--the simple past. But sometimes things are still happening, even though they're in the past tense, or sometimes a character is discussing something that goes into the past past, or the past perfect.
When I'm beta reading and come across something that happened in the past perfect, but is written in the simple past, I'm often thrown out of the story trying to figure out *when* the action is happening. Using the correct tense keeps the words invisible so the reader can follow and understand the story.
The good news is that these three subgroups follow the same pattern across the tenses.
Present Tense--the tense in which things are happening now.
Simple Present: I write a book.
Present Progressive: I am writing a book.
Present Perfect: I have written a book.
Future Tense--the tense in which things are going to happen.
Simple Future: I will write a book.
Future Progressive: I will be writing a book.
Future Perfect: I will have written a book.
Resources for Further Study
Progressive tenses--an overview of how to form them
Guide on when to use progressive tenses
An overview of the tenses by Purdue's Owl Online Writing Lab--fabulous resource for all things grammar.
Danyelle Leafty (@danyelleleafty) writes MG and YA fantasy. In her spare time, she collects dragons, talking frogs, and fairy godmothers. She can be found discussing the art of turning one's characters into various animals, painting with words, and the best ways to avoid getting eaten by dragons on her blog. Her serial novel THE FAIRY GODMOTHER DILEMMA can be found here. The first 12 chapters of THE FAIRY GODMOTHER DILEMMA are available here.