How do you develop narrative voice in non-fiction?

My first book was in question and answer format. This turned out, in retrospect, to be really useful for developing a personal narrative voice, although what I was writing was a knitting reference book. After some thought and discussion, I decided that the questions would be in the first person ("I") and the responses would be in the second person ("you"). And that I would abandon this and move to the third person when it became obviously contrived or in longer explanatory sections. Looking back on it now, I realize that this made my book have a much more personal, helpful voice than it otherwise would have had.

Another benefit of the question/answer format was that I could craft each question and each answer very carefully, almost as if each were a prose poem, carving them down to just the essentials.

Friday I'll be meeting with my editor to map out my second book. It's another knitting reference book. Although I proposed it as another question-and-answer book, they've decided to make it a more traditional book. Now, of course, I'm feeling insecure about how to structure and style the prose it so that still has that personal, approachable feel to the reader.

Does anybody out there with more experience than me have any tips? I'd love to hear how you approach your business/technical/reference/historical or any other sort of writing to make sure it doesn't become dry or academic, or a user's manual.

Thanks for responding. I confess, I was sort of hoping this would generate a philosophical discussion of the craft of writing. But it sounds so far like my natural tendency to wing it and see how it turns out is what you'd do too.

Do you suppose there are any writing exercises that might be useful? For example, I could try to explain the same thing to an absolute beginner, to an average knitter, or to a very advanced one and see just how much the explanation changes. I think it's important to keep the audience in mind at all times, but I'm not always sure that it's useful to write to the same level throughout the book because it narrows the potential market for it. If I write specifically for beginners, they may not want to plunk down $20 for my book, and the more experienced knitters (except for my very own groupies) won't be interested.

Do you see it as a problem that parts of the book may be geared more to beginners and parts to the more experienced?

Hmm. Now I'm speculating on whether I'd explain it differently to a friend than to a stranger. I like the idea of a sit-down-next-to-me-on-the-couch-dear reference book, which is pretty much what I achieved in the first one. But it's so much more obvious in the question and answer format.

The thing is, I know from my teaching that I explain things competely differently to people who are computer programmers or who are comfortable with math than I do to people who come to knitting design with a tactile design background (like potters, for example). Unfortunately, I don' think that adjusting my discourse that way in a reference book is going to be helpful. It will just give the readers the impression that I'm schizo.

What kind of craft books do you buy?

Thanks Cath and TDN. I'll take your suggestions under advisement.

Thanks to everyone for replying and making suggestions. I get the impression though, that you're working theoretically, suggested what I could do. What I really wanted to know was how you, as a writer, approach this. If the advice you gave is what you actually do, fine, but I'm curious whether anyone but me even worries about this.