Most people who have been writing fanfiction for any length of time have a horror story or two about a bad beta. There's the person who just doesn't understand your work, who has very different views of the fandom and its characters than you do and consistently says, "bad characterization" when the real problem is vastly different interpretations of the character, or nitpicks at things so much that it makes the story no fun to write. There's the person whose grammar or other writing skills are at a lower level than yours, and so never finds anything to correct. I've had a few betas who just turned out to be so annoying or weird that I couldn't work with them (again, not naming names.) Most commonly, the problem with betas is finding one who will follow through and read your story — or just finding one at all. I spend more time posting beta inquiries or emailing beta requests than is probably healthy. I have a form letter that I wrote up so I could copy-paste and add the relevant details when I'm looking for a beta. That's how many times I have to look for a new one. I've even considered writing up a permanent beta request post that I can link people to. Most requests don't get a response, and of those that do, I would say one out of five people actually agrees and follows through to read the material I send them.
Some of that is probably because my stories are ridiculously long, and I don't really write in very many "cool" or popular fandoms. I use examples from my Stargate and Star Wars work when I write this blog series because those fandoms are more well-known, but neither one is enjoying the height of its popularity anymore. Most of the franchises that I write for have pretty small fan communities. My experience is not unique, though. A quick browse through forum threads or LiveJournal communities or even Tumblr posts related to fanfiction will show way more people looking for beta readers — begging for beta readers — then there are beta readers volunteering their services.
So, the odds are, if you're writing a story of any length, you're going to have to get multiple beta readers for different periods of time. If you're like me, there will be long stretches when you don't have a beta reader because the ones you had are busy or have other commitments. Having a beta reader is fantastic, and I recommend it whenever possible, but if you don't have one, here are some things you can try. (Disclaimer: most of these don't work overly well for me, but you may have different experiences with them. Try them out and see what works.)
For general spelling/grammar issues, missing words, etc.
Put each chapter aside for a week before you start to edit it. If you can't wait a week, put it aside for at least three days. This will help you get some distance from what you've written so that when you are editing it, you will be less likely to feel like you know what it says and end up reading what is supposed to be on the page instead of what's there.
Print out your draft and make your edits in pen or pencil first. This is a pain in the ass, and it takes longer than it would if you were editing on your computer, but it forces you to slow down and take a look at what is actually on the screen and/or on the page. Because your edits then need to be transcribed onto your computer, you have an added layer of proofreading that may help you catch errors you didn't see before. You also have more time to think about what's been written and decide if you need to make any changes to the story content itself.
Read the story out loud. As with printing it and doing your edits in pen or pencil, this may help you catch errors because your brain has to process more kinds of input.
Read the story from the end to the beginning. It won't make sense, and that's the point. This may force your brain to pick up errors that you would otherwise skip over.
If all else fails, try using Windows Narrator. (It's a utility installed on any Windows PC that will read back text portions of any open document. I'm not sure if there's a similar feature on Macintosh computers, but you may be able to find a free text-to-speech utility by searching online.) The computer voice is horrible, and it will make mistakes in pronunciation. It doesn't sound at all natural, but it will read the words that are actually on the page. This one has actually helped me, because I have to listen carefully to what it's saying and make sure the words are correct.
To open Windows narrator, click Start> Accessories> Ease of Access> Narrator.
For Continuity Errors, Characterization, and Questions of Plausibility.
The best way I know to maintain continuity between chapters that were written over a long period of time is with lists and charts. I know, I know. That's a lot of work. It's a pain in the ass. I really wish that I had thought of doing it earlier, because even though it takes more initial work to set up, it would've saved me a lot of headaches. Here's what I do:
Make a list of all the major players in the story.
Make a separate list of all the major plot points and subplots in the story.
I keep these documents separate from my charts because they will change over time. I know that my plots will diverge from my outline, and subplots may or may not end up working the way I thought they would. Lists can serve as a quick reference guide that I can scan a lot more easily than I could scan a large chart, and I can update them with a lot less hassle if I'm in a hurry.
Then I make two different charts or spreadsheets. The first one has the major plot points listed across the top of the page. The characters names are listed on the left, and then the table cells cover what happens to them in connection with each plot point. (Some people like to use this format as an outline; I prefer to use it as a method of keeping track of what I've written.) The second chart lists the chapter numbers across the top of the page, and again, the characters names on the left. If you are good at keeping your chapters on track with your outline or what you think is going to happen, you can probably make this ahead of time. Since my stories take on a life of their own and my characters do things that I was not planning, I leave it blank and fill it in as I go.
Make sure that you leave time in your writing schedule to work on and update your charts as you go. Otherwise, they will become outdated and completely useless, not to mention overwhelming when you go to try to fix them. This is something you might want to do during that week between finishing your rough draft and editing what you've done.
For dealing with questions of plausibility and characterization, I found that the best thing to do is to ask someone what they think of a specific plot element, scenario, scene, or section of dialogue. Most fans are nice people. Even if they don't have time to beta read for you, they'll probably have time to answer one or two specific questions about your story and point out any problems or conflicts with canon.
Do you have any other ideas or suggestions? What have you found is the best way to get by without a beta reader if you have to?