I'm a librarian and there is a site, EarlyWord, which I visit regularly, that helps me to find out what's "hot" in the book world and what titles I should make sure I order for our collection. I want to share it with you because of one feature that a children's writer should be aware of. It's "Download Publisher Catalogs," and you find it way down on the right hand side of the page.
When I started writing for children, the advice was, "Send for publishers' catalogs and STUDY them so that you can get a feel for the house and target your submissions." This was a costly endeavor! I fortunately got many at the library I worked in. Or, I picked up catalogs at NE-SCBWI conferences. And you know what? They were beautifully printed in color on good quality paper--and they were HEAVY. I didn't collect half as many as I would have liked. Now, life is so much easier. You can go to a site like EarlyWord and simply download as many catalogs as you would like. No paper. No postage. No clutter!