Writing is about editing. We all know that. However, that doesn’t answer the question when to edit.There are a few basic options.
Write a draft straight through, perhaps making notes on things to be changed, but use a one directional process. Don’t second guess yourself.
Write a good chunk of the manuscript and then revise. This level of revision may involve deleting parts, adding parts, re-ordering scenes, and, of course, fiddling with words.
Revise each page as you go. Perfect the page then move on.
Pros and cons can be argued for each process.
Write straight through and you risk going far down a path you later eliminate entirely. On the other hand, no time was lost in detailed revisions prior to scrapping entire sections.
If you revise section by section too much time can be put into the earlier sections and less into the end. Sometimes it shows!
Aim for perfection and prevent yourself from moving on. What happens when those perfect sentences end up not belonging in the manuscript at all?
I suspect that authors evolve. For example, the more experience you gain the more confidence you might have in a story arc (and therefore revise each page to perfection as you write). Sometimes the story itself drives the path – the words are flowing and stopping to revise is counterproductive.What is your early editing path? Revise, revise, revise or first reach for the end?