After I've written a first draft and revised and revised and revised until I can't see it any more, then I turn it over to beta readers. This is currently where I am in my process. Here are some tips that I've learned about this stage along the way:
Create Deadlines. At first I naively, grandiosely assumed that people would just read my manuscript right away. Well, people have lives. They put off reading. They might not, gasp, like what I wrote. So now if I ask someone to be a reader, I ask if they can finish within a certain amount of time. I usually say a month. That seems reasonable to me.
Less Is More. This is all a personal preference, but I generally ask two, maybe three people to read my draft. It makes life less complicated. I know that I still have the editorial process in front of me, where my developmental and copy editor will also be chiming in with their thoughts. So two or three readers works for me.
Choose Carefully. Do you need an expert on a subject to chime in? Who do you know? Or who do you know who knows someone who knows? I also think about compatibility here. I want someone with a kind, thoughtful manner who will take this responsibility seriously. My friend and neighbor, Larry Brown, fits this criteria. I always ask him to be a beta reader, and I look forward to our meeting, when we sit at the table, both with drafts in hands, and I take notes while he tells me what he thought. When you're choosing your beta readers, think about what you might need checked and how you like feedback expressed to you.
Provide Guidance. Where do you need help? What is nagging at you? Where are you unsure? Tell your beta readers a few things when you give them the draft. Sometimes I'm more cagey about this step. I don't want to unduly influence their reading. But I generally feel that if something has been bothering me and and I can't figure it out, it's better to just share that with my beta readers rather than having them get to that point and think, "Oh, this is a mess. Poor dear. I'm going to have to tell her." If I tell them about my concerns, it then becomes a moment of "This is what she was talking about. What would be my suggestions?"
Reward Them. I give beta readers the book when it is published. I also often will do some sort of swap: editing or reading of their project in the future or some measure of thanks for their assistance to me. I want them to know how much I appreciate their feedback.
Remember You Have the Last Word. One of the reasons why I am not in a feedback group is because I have the unfortunate tendency to want to please people. If I was receiving constant opinions, I would be continually changing my story and forgetting why I wanted to write it in the first place. When I receive feedback from my beta readers, I listen and assess. Most of the time, they have a point. But sometimes I keep it the way it was or I shade it or I go in another direction that I think will work instead. In the end, the writer needs to have final say.