I’ve gone through several rounds now both getting feedback from beta readers on my first novel, and acting as a beta reader for other writers. I’ve emerged older and (hopefully) wiser, thanks to quite a few mistakes. Here are some things I’ve learned along the way.
If you’re asking people to beta read for you:
(1) Don’t send out incomplete or unfinished work. This sounds contradictory—obviously the work isn’t ‘finished’ if you’re looking for feedback. What I mean is, if you know that you need to go back and tighten the writing up or fill in some of the dialog, don’t ask people to read the work yet. Fix all that stuff, and then send it out. Also, don’t send out a few chapters while you finish the rest. In order to get a true reaction, your reader needs to be able to read the entire thing in a way that flows naturally for them.
(2) Pick readers that are appropriate for your manuscript. Make sure your readers like your genre and are in your target demographic. If you have a 20-year-old male read a book intended for 40-year-old women, his feedback will not be helpful, and vice versa. If you’ve written a mystery and your reader hates mysteries, you're probably not going to get what you need.
(3) Pick readers that have the right skill-set. I’ve found that the best beta readers, by far, are other writers. People who are prolific readers can also be good. But friends who don't read much are probably not the best bet, even if they do want to do you a favor. Another ‘skill’ you need is the ability to be honest, so be careful when asking friends. If both of you are comfortable with the possibility of a negative reaction to your book, great. But if your friend is worried about how their honesty will impact your friendship, then they won’t be giving you real feedback anyway--so what’s the point?
(4) Give your readers a time-frame. Ask them if they can get back to you by a certain date; if they can't, thank them, but find someone else. Once you're underway, send your readers a reminder about a week before your due date—time flies, and they may have forgotten. If you haven’t received feedback by the due date, send a gentle e-mail asking about the status; if you still don't hear back or they don't follow through after another week, find another reader. Don't make the mistake of thinking, "oh, I'll give them just one more week/month...", without asking someone else in the meantime. If the original reader does get back to you, great! But if they don't, you'll be out of luck if you haven't asked anyone else.
(5) Specify what you want from your readers. If you are looking for feedback on what works and what doesn’t, but don’t yet need feedback on typos/grammar, make that clear to your readers. Otherwise you may get back a line-edited manuscript that gives no insight into whether or not you’ve told your story effectively.
(6) Use at least three beta readers. A widely bandied-about principle regarding feedback is the ‘rule of two’: if two people agree that something needs to change, you should consider changing it. So two should be enough, right? Wrong. If you only have two readers, you risk ending up in a situation where the two readers disagree on some, if not all, of their feedback (yes, this has happened to me!). And then all you can do is stare at the feedback and wonder whose you should take, until your head explodes. And brains are really hard to get out of the carpet. With three readers, you have a built in tie-breaker. And if you can get more than three—awesome!
(7) Remember you don’t have to take any suggestion you don’t agree with. Just make sure you aren’t rejecting it out of stubbornness, fear, or hurt. Consider it with an open mind, maybe even do some re-writing with the suggestion in mind, and if you just believe the suggestion doesn’t work, go with your gut. It’s your piece/book, and you’re the one that has to proudly hand it to agents/publishers.
(8) Don’t take the feedback personally. People aren’t spending hours of their time just to hate on you. Seriously now. And if they are, they have waaay worse problems than you do. Always assume the reader is trying to help you, because they really are.
(9) Thank your readers in a genuine way. I’ve had people not respond when I sent my feedback, and I’ve had very passive-aggressive responses that thanked me but let me know they were upset about what I'd said. On the other hand, I’ve had lots of people thank me in a way that let me know they really appreciated my time and my insight. Since I don’t have time to beta read for everyone who asks me—guess who I’ll be willing to read for again?
If you’re beta reading for someone:
(1) Remember that this is extremely important to the author. Not important like ‘Hey, can you stop on your way and pick up some ice?’ but important like ‘This is my livelihood and may make the difference in my ability to pay rent.’. If you say you’re going to get back to them in a month and it takes you six months, that’s a five month delay to their potential paycheck. You might be thinking ‘Hey! I’m doing them a favor!’ You are ONLY IF you take it seriously and do it in a timely fashion; otherwise, you’re doing damage. This isn’t checking a book out of the library and forgetting to read it before it’s due. Imagine how you’d feel if your paycheck was sent to a friend, and for months they kept forgetting to bring it to you. Not cool, right? Neither is making your author wait months for your feedback when they’re trying to write and publish a book.
(2) Be honest with yourself and them. If you are worried that you can’t be honest with them, or you know there’s no way you can get it done in the time frame they’re requesting, don’t agree to read for them. If you truly believe you can and then something changes, tell them as soon as you can so they're able to get someone else to do it. Keep that paycheck metaphor in mind.
(3) If you’re not sure what your writer wants from you, ask them. Maybe they weren’t very clear to start with, or maybe you’d had one too many margaritas when you were talking about it with them. Either way, ask what they need from you, don’t guess.
(4) Respect your author’s writing process. If they tell you they aren’t ready to edit for typos and grammar yet, don’t send them back a manuscript edited for typos and grammar. Your author may have to completely rewrite scenes and even delete entire scenes; they will be putting new things in and taking old things out. No matter what, by the time they do what needs to be done, your line-editing (typo/grammar feedback) is obsolete. But during a final round of feedback, catching typos and grammar errors may be crucial. Just don’t waste your time and theirs doing the wrong thing at the wrong time.
(5) Respect your author’s feedback process. Imagine this: you just sat in a big pile of something really gross and didn’t realize it. You’d want someone to tell you so you can fix it, but that doesn’t mean it's the most pleasant moment in your day, right? You’d probably have an ‘oh crap!’ moment, run to fix it, and then be very, very grateful. Along the same lines, writers want to know what isn’t working, but that doesn’t mean they’re going to instantly yell “Woo-hoo! I’ve never been so happy in my life, this feels so good!’ when they find out what it is. It’s a serious moment, and they may need a little time and space to read, think, and process. Trust that they know how to do this in a way that works for them. If they ask for your feedback in writing, don’t insist on giving it face-to-face over coffee, and if they want it face-to-face, don’t insist on giving it over text message. Some authors want a written record of your feedback so they can go back and consult it repeatedly as they work. Some authors want the vocal and visual cues from your face when you tell them what you think. Unless it’s extremely inconvenient for you, honor their wishes.
(6) Re-read your comments before sending. Remember things come off harsher in writing, and remember that you can be honest without being harsh or cruel. And always-always-always remember that your author wants to know what worked as well as what didn't. Find something nice to say, and make sure that even the negative is couched in terms of 'this can be improved' rather than 'this sucks'.
(7) Don’t be offended if your writer doesn’t make the changes you suggest. This doesn’t mean they aren’t grateful, they are. But there are many reasons why they might choose to go a different direction. Maybe you felt something was too obvious, but all their other readers were stymied. Maybe a scene was too gory for you, and made you want to vomit—but that’s exactly the reaction they were going for. Maybe you’re just far more insightful and awesome than the average reader. Your author is trying to make decisions that work, based on a variety of opinions, including yours.
Above all, whether you're the reader or the writer, remember that you've been given a compliment, and you are valued. Someone is trusting you with their blood, sweat and tears, or someone is giving up their precious time to help you. Keep that close to your heart no matter which role you're playing. :)