I do this professionally so my take will be biased. Take it with a grain of salt.
If you have a particularly keen eye you can do a decent job editing your works by yourself, but it's a rare talent and it's not something you can count on. Even editors need to get their writing edited by another person.
A few reasons for this:
- When you're familiar with a piece, you develop content and structure blindness. Put differently: your familiarity is a weakness during the editing stage. You can ease this a little by setting the manuscript aside for a long period of time and relying on good old-fashioned memory loss to try and counter it.
- A different set of eyes will come with a different perspective, and sometimes that's exactly what your story needs to make it go from "good enough for me" to "good enough for everyone else".
- An editor has a different set of skills and a different approach than you do as a writer. Their job isn't to write, it's to take what you've written and make it better. An editor who makes your content stay the same or sometimes get worse is a bad editor. You should feel as though your piece has gotten better, objectively, even if the feedback from the editor was harsh. (Some editors employ a Feedback Sandwich approach where they package criticism between two compliments because it's common for authors to take offense. That's understandable: writing is emotional and close to the heart.)
- If you're stuck, seeing what someone else does with it can give you the answer you're looking for.
Many well-to-do authors have a fairly expansive editing process for their books. Those in the self-publishing space frequently don't because it can get expensive. A round of copyediting from an experienced editor can cost in the neighbourhood of $2000 easily. Imagine what this is like if you also get some developmental editing done, multiple rounds, professional beta readers, and then finally a pre-format and post-format proofread. Not to mention the costs of typesetting and design. A book, if you invest, can cost upwards of $5000 to $10,000 dollars without particularly splurging.
Most don't have the option of spending that much so they skimp where they can. That makes sense and it's not something you should feel bad about. A lot of this you can learn how to do a passable job in. I say "passable" intentionally. You'll get it done and the results won't be offensive, but you'll notice it's not to the standard of a professional. In self-publishing this is fine. In traditional publishing, you better hope you have a good contract with a decent publishing house who handles this themselves and doesn't make you foot the bill. Not sure if that's of interest to you, but I'd strongly recommend avoiding any contract that tells you you're on the hook for manuscript and marketing costs.
Since you're working with short pieces right now, you don't need to match the expansive editing process above. With short stories you can get by on your own or just get a fresh pair of eyes to critique and proof it. I do that but I'm not pitching to you here; instead, I'll tell you what the authors I've worked with do and what I recommend others do themselves.
If you've completed the first draft of a piece, let it sit for a couple weeks. Don't look at it. Then, when you go back to it, rewrite it from scratch using the first draft as your outline. Don't edit it piecemeal. Rewrite. You'll change certain sections drastically, organically resolve plot holes, and you'll probably remove and add a few things while you're at it.
Do this until you think you've tightened everything up as best you can. With a short piece, don't bother with developmental editing. You just did that yourself and there isn't much a professional can tell you at this length beyond "Start over, this isn't good." or "It's fine, keep improving it." (IMO.)
When you're satisfied with your own work, you can get a couple beta readers. I recommend paying for them but if you can find free ones who actually do what you ask, cherish them. They are rare. Many authors abuse the idea of a beta reader and ask them to edit the piece or suggest specific changes. This is a breach of protocol from my point of view. What you should get from a beta reader is the following: an outside perspective on the story, comments on impactful or problematic sections of the prose, and feelings about specific concepts (such as an emotional scene, or general characterization). A small form is all you should expect from a free beta reader. Paid beta readers often have their own forms along with the option for you to specify what you specifically want feedback on. If you want beta readers to (ethically) catch errors, you'll need to pay them like an editor.
At this point you'll know either of these things: you've got something good or you've got something that still needs tuning. If the latter, take the time to assess the feedback you received from your beta readers. Do you feel they're right? Why do you disagree with them? If you're still uncertain about the value of their feedback after a week or two, get another beta reader and this time ask about the things you got questionable feedback on. Use them as a measuring stick for the obstacle you're facing.
After you've received their feedback, this is where your journey in the beta reading process should end. Not only are short pieces not worth this level of investment (even up to this point is questionable, but some short pieces carry with them a lot of cachet and dollarydoos) but you can easily get trapped in a loop of circular reasoning where you're constantly doubting and constantly seeking someone to ease that doubt (and then they replace that doubt with a new one). Allow yourself one extra round of beta reading to address previous concerns. After that, either go back to editing the piece or move forward.
We'll assume you moved forward. I do recommend for any piece that you're submitting to a magazine or litfic press that you get it proofread before submission. A proofreader can range in costs from 0.002 a word to over 0.01 a word. It depends on their experience level, the genre, and the level of complexity in the piece. The cost can also be impacted by whether or not you want to give the proofreader the agency to make sentence changes or provide feedback on structure as their role will have expanded to also providing you a "manuscript critique" or "manuscript evaluation".
What's important to keep in mind here is that you can disagree with your editor, especially on style choices, and that any editor worth their salt can talk to you about why they made the changes they did. Sometimes it boils down to personal preference, sometimes it boils down to their preferred style guide, and sometimes it's about consistency and what they felt fit your "voice" most accurately. A good editor can explain this to you. An editor who can't is worth side-eyeing.
Just in case: there are different kinds of editing. The lines are blurred between them frequently but if you ask for a specific kind of editing, you should temper your expectations.
- Manuscript evaluation: This is the first step in the editing process. Some editors require this before they do any editing. Most (in my experience) don't. A manuscript evaluation is a read-through of your piece where they highlight things that need changing. This allows the editor to assess what kind of editing it needs and also whether or not they're the right fit for the job. It is also an invaluable tool for the author as they can take the evaluation and make their own changes before handing it off to an editor.
- Developmental edit: This is the next step. A developmental editor will tackle the big picture. Small pieces rarely need this kind of editing because they're simply too short and limited for it to receive any appreciable ROI. However, to be aware, a developmental editor will tear apart your story (affectionately, of course) and tell you where and how the story fails. They'll recommend character changes, lore changes, story changes, all of it. It's their job to make your story go from an unpolished draft to something that follows standard literary conventions or breaks those conventions in a compelling way.
- Line edit/Copyedit: I put these two in the same category because many editors instinctively blur the line between them. It's extremely tempting to be a little more involved with the manuscript if you're doing a copyedit and the editor will naturally transition into doing a partial line edit. The difference between them is simple: a line edit involves restructuring your paragraphs, removing sentences, adding new ones, changing phrasing, and beyond. An editor who does a line edit will work directly with your "voice" and they'll try to make it better while still preserving what makes you, you. Meanwhile, a copy edit will focus on the more technical details. They can do line editing, and most often end up doing line editing, but that's not what they're specifically for. A copyeditor will look at grammar, idiom use, scene separation, and more during their round of editing. If you get this done, you need to ask the editor to what extent they go in their editing. I recommend getting an editor who is comfortable doing line editing and includes it in their copyediting. It saves you money and you still get the same work done.
- Proofreading: You get this done just before you send the piece to a designer/typesetter, and then again afterwards. For short pieces, you get this done right before you submit it to the applicable press/competition. It is not a proofreader's job to format the piece but you can ask them to and they'll get back to you on whether or not they can do it and if it'll cost more. They'll ask for the formatting guidelines of the competition you're entering. A proofreader is limited in what they can change: they cannot (and should not) change any phrasing or positioning unless it is objectively incorrect. Style changes don't apply here unless it is a question of consistency. A proofreader will make your writing stand up to scrutiny from a spelling and grammar perspective but they have no say on content and structure. In other words, they catch what you and the copyeditor didn't catch.
Worth keeping in mind here is that you won't get a 100% error catch rate. 90% is a good metric to shoot for. If the editor finds 90 errors and you find 10 after publishing, they still did an adequate job (depending on the errors that were missed). Shoot for 95%. Anything above that will be a surprise and one you should be grateful for. Perfection is not something that can be reliably offered, even through multiple rounds of editing, and you shouldn't expect that.
This got a bit away from me, but I hope something in this wall of text proves helpful to you.