I did that yesterday. I opened a fiction draft set in Kuwait, reread my editor's comments, took a breath, ate some panic chocolate, ordered a mocha for delivery, checked the news, opened my email, stared at the ceiling, rolled my neck, and got to it. Cut cut cut. I cut three characters at her suggestion. I swapped a page of backstory for a few sentences. I puzzled show versus tell.
Always a puzzle for me, that sweet little writing workshop phrase.
I realized two things:
I don't trust the reader very much. That's why I want to saddle you with five paragraphs about why Jeff took a job with a contracting company in Kuwait. I need to learn that those five paragraphs about the ex-girlfriend and parents and brother and forklift job in Milwaukee - those paragraphs are for me. I need to know Jeff first. But you don't need his elementary school report card. You need me to trust you to see what I show, to build a Jeff in your reader mind without me telling you.
Second, from reading loads of short fiction: most really great short fiction pieces are tight on two or three characters. That's it. When I draft I spin a dozen characters that all seem Very Important, even in minor roles. But when I cut three characters from yesterday's draft, the piece was better. Now the reader can follow Jeff without the distraction of George and Honeybee.
Okay, a third thing:
Revision is where the risk is for me. I can wander through a short fiction piece until it's forty pages long. I want to give every character a backstory. I want the reader to know exactly how these characters are knitted together. But I don't know how to knit. What the reader gets is a mess of yarn snaking from one minor character to another to another so that halfway through a piece, the narrative is lost. When I revise, I must be willing to risk cuts that hurt a little, to keep the whole narrative.