Many organizations exist for the benefit of those who love to read or write children's books. Here are four Canadian organizations of which I'm a member. They can link you to a world of books, publishers, and advice.
The Canadian Children's Book Centre (For readers, writers and everyone who supports Canadian books for young readers.)
The Society of Children's Book Writers and Illustrators (Advice, information, and networking for writers with all levels of experience.)
Canadian Society of Children's Authors, Illustrators, and Performers (News, advice and information for professionals.)
Quebec Writers' Federation (News, support, and many Montreal-based events.)
Many writers, agents, and editors offer the lessons of their long experience to help new writers write and market their work. Here are a few to start you out.
Ten Rules for Writing Fiction (This article differs from most of this ilk because it has ten-tip lists from some of the world's best contemporary writers in a variety of genres, from Elmore Leonard to Roddy Doyle. I particularly like Margaret Atwood's airplane-writing tip.)
The Purple Crayon (Articles on writing and publishing childrens' books.)
Nathan Bransford's Publishing Essentials (Articles on selling fiction from a former literary agent.)
Daily Writing Tips (A website that offers just that, with archives of kazillions of tips.)
Just keep in mind that you can spend too much time reading writing tips at the expense of actually writing. So rein yourself in if you find you're regularly spending entire mornings reading tips. Catchy one-liners don't really encapsulate much about the writing process.