Fuse #8 pointed me at Jane Yolen's journal, wherein she talks about how she's writing (and, sometimes, tearing her hair out over) her current picture book. A snippet:
Difficult? A picture book? O, ye of little knowledge. To remind you: a picture book is usually 32 and occasionally 40 pages long. Half or more of it is pictorial. The trick of writing one--so far as there is a trick--is to be a prose writer with a poet's sensibility. Or a poet who is comfortable with story. Furthermore, an historical picture book needs to be able to boil down a biography or a part of a biography into a followable line with illustrate-able pages.Y'all, this is why she's Jane Yolen. Unfortunately, her journal won't let you link to individual entries (Jane. Wordpress. Is all I'm sayin' here. Please?) so just scroll down the page or do a quick search to find the first entry, "Interstitial Moment 1 of 3."