Jessica: I’ll echo every one’s else’s sentiments that you need to figure out what works the best for you. I also think it depends on what sort of first drafter you are.
For me, I did exactly as Xaenyth did. The minute I knew other people were reading what I wrote, I froze up. Even after I told them to not offer feedback directly to me, it was still like writing in front of a huge crowd. I found myself writing less for me, and I worried more about what my readers would think.
My first drafts are legible, but there are always messy bits. I decide I don’t like a character’s POV and drop it. I am too lazy to look up a secondary character’s eye color. I randomly change direction. Sometimes I make radical changes, and knowing that people were following along made those changes harder. I would have to take the time to explain what was happening instead of moving forward with the story.
So now, I always write my first draft with the door shut. I’ll do a lot of brainstorming with my friends, so they often know what the story is about, but they don’t read the book until I revise the first draft. I also think it’s a better use of their time, because they aren’t going to ding me for things I already know is wrong.
But I read my friend’s rough drafts as she writes them. She doesn’t often change a lot in the book though, so her revisions are usually about increasing tension and tightening up scenes. I can cheer her on and give her motivation. It works for her, but not for me.
Another thing I can tell you that while learning after you wrote the book that you made X mistakes is annoying, sometimes it can’t be helped. And just because you have someone reading along, doesn’t mean they are going to catch some big mistake you’ve made. Having someone read along can be great for your self esteem, but you’re always going to find stuff to fix and change in revision.
Not that you don’t already know this, but it sounds like you want to be as prepared as you can. Which is good, but I have learned from very hard experience that you will make certain mistakes sometimes, beta reader or not. And as annoying this mistakes are, it will help you in the long run.
What I have done as a middle ground between having people read along, and writing the book with huge plot holes (something I am famous for. Some magic aspect will make perfect sense to me, but upon hearing about it my friends tell me it makes no sense and it’s back to the drawing board), is talk in depth with at least one person about the plot. I go back and forth with them, hitting the highlights. I talk about the major magic aspect in the book, and anything else that might be suspect.
Not only does this help me develop the book better, but it catches a lot of plot holes and mistakes before I even write the book.
So yeah. Just play around with what you think will work for you. 😀