|Sketch snipped from Matt Walkden's Art.|
A lot of artists use construction lines to help them understand and map out the underlying forms of the figure they want to represent. The sketch above helps show this. These underlying construction lines are a little bit like creating an armature for a sculpture--it provides a foundation on which the drawing can be built. Later, when the drawing is more fully developed, the construction lines get erased.
Writers do this a lot, too--except our construction lines involve all kinds of writing around the subject. To get to know characters, we often have to write out their whole backstory. When we write a conversation, we write ALL of it, even the unimportant parts. It helps us to understand the depth and breadth of what we want to convey. In the revision and/or editing process, however, we go back and cut out the traces of this developmental writing.
The only tricky part is that, in drawing, it's easy to identify and erase the construction lines, but it's not always so easy in writing to identify what makes up the developmental content vs the essential parts of the story. That's where objectivity and having a good, third-party editor can be really helpful. It's also helpful to remember that, while the developmental writing was a really important and valuable part of the process, its purpose has been served and you can respectfully remove it, guilt-free. Be kind to your construction lines, but don't forget that--like a scaffolding--they need to be removed at the end of the day, so the Great Wall you've built can stand on its own!