Three days of my allotted eight done.  About a third of the way through the book.  Rather enjoying myself.  I wasn't sure if I would, to begin with - the first day was quite a tough one, and something of an assault on my self-belief.  I'd always considered myself quite a decent cold-reader, with moderately good diction - but this belief was based on a slightly skewed experience:  That of cold-reading scripts.  Scripts have one particular characteristic that other pieces of text do not - gaps.  When cold-reading a piece of dialogue, especially if it's a conversation, there's usually a liberal sprinkling of gaps - while another person is speaking; while one's own character thinks what to say next; "pauses for dramatic effect".  It turns out that what I'm good at, is reading ahead, and having the next phrase, already adorned with appropriate inflection, cued up in my head ready to fire.

Audiobook reading, I've quickly discovered, is a very different technique.  At least, in the case of a non-fiction book like the one I'm currently working on.  Why?

There are no gaps.  The occasional paragraph, yes, but that's about it.  Where there is conversation, the reader must provide both sides of it - no opportunity to prepare your next, perfectly-inflected line while another actor is speaking, because the other actor is you!  Dramatic pauses are possible, but there's precious little chance to see the opportunities coming before they're upon you, and then, if you're not careful, the moment has passed, you didn't seize the moment, and read ahead, and you're back into the onslaught again.

It's one of those "Zen" skills, it seems, like so many things.  Direct path from eye, via subconscious, to mouth.  The conscious mind is watching, certainly, directing the performance, but the moment it interferes, the flow stops, and every second word is a fluff.  To my surprise, I found the most successful passages to be those where my conscious mind had drifted off, and was thinking about something entirely different.  At one point I realised I'd spent something like a minute worrying whether I'd turned my phone off, and how embarrassing it would be if I got a call or a text.  As soon as I spotted myself doing it of course, in waded the posturing bully of my consciousness, and I tripped over a simple word.
Definitely getting easier though.  Yay for the learning of new skills!