Today’s picture book market is very different from when I was a child. The book market is more selective. There exits an underlying pc culture. Very few publishers like in the past take direct submissions from new authors. So now you have written a children’s book, but does it cut the mustard (meet current standards)?
The first step is to compare your book to what’s currently written. Go to your library and read. Read in your genre, then read books out of your genre. But read current books. Water is Water by Miranda Paul is a perfect example of a nonfiction narrative that varies vastly from the expository/factual nature of picture books in the past. Books like I Talk Like a River explore the world of a stutter and address personal issues that kids face beyond friendship or bullying. So, read and find your mentor texts.
The second step is to know your craft before sending the query letter. Editors and agents get so many manuscripts that if they are not near perfect, they toss them. It’s like a resume filled with grammatical errors or false information. Research your agent, editor, or publishers. Make sure they are open to submissions in your genre.
The third step is to use the tools at hand. Microsoft Word has a review function that reads your work out loud. Use Grammarly or one such program to edited your work. Don’t pay someone like I did to take the extra space from behind the period when you can do it yourself. Crtl A copies, and Crtl H brings up a dialog box to make edits all at once.
Lastly, participate in a good critique group. Not an online, never see your face type but a Zoom group. It makes people accountable for what they say and why. A picture book must allow the reader to see for themselves what you are trying to say, not telling them what you think. For young readers, you are helping to develop their imagination. A mind free to think will imagine, reason, and then decide to act. (My synopsis line from a CS Lewis study with Hillsdale college.)
I will end by saying I had made every newbie mistake in the book by sending my manuscript out before it was ready. Take your time, learn the process, research, get your work ready, then submit.