While there are plenty of websites, books and other resources about #kidlit, here are some that I found especially helpful (and continue to do so) in my own life as a picture book author.
Memberships and Courses
SCBWI: Whether you are an aspiring author or have several published books, an SCBWI membership is equally valuable. From free virtual events to paid conferences, this is a gold mine for children's authors.
Children's Book Academy: The annual writing course is by far the best picture book writing course I've taken. You can have unparalleled access to Dr. Mira Reisberg and an amazing faculty of editors and agents.
12x12: A fabulous membership-based community encouraging writers to pen down one picture book a month.
Highlights Foundation: A plethora of workshops, in-person and virtual. Plus writing retreats to inspire and nurture your creative self.
Storyteller Academy: Memberships, courses and coaching.
A few others: Picture Book Summit, Kidlit Hive, Journey to KidLit, Writing Mastery, BBC Maestro (Julia Donaldon's course), Lyrical Language Lab (one of the best for learning to rhyme).
Blogs
Here are a few blogs to keep you updated with upcoming books, agent/editor interviews and author chats amongst other kidlit news.
Kidlit411: A comprehensive guide to everything kidlit. Active on facebook too.
KathyTemean: You can win books by entering contests frequently.
Literary Rambles: Check out their agent spotlights!
Only Picture Books: A weekly rumpus of picture book things.
Mary Kole: Besides being an editor, her website has useful articles for writers.
Storystorm: Active in January of each year, where you will be inspired to come up with one picture book idea a day!
Purple Crayon: Harold Underdown has tons of info on the publishing industry.
Agents and Publishers
Publisher's Weekly: This is paid but the weekly newsletters are free.
Manuscript Wishlist: All things agents and editors are looking for.
Manuscript Academy: Writing consultations and agent/editor critiques.
Twitter: Many agents actively tweet when they open to queries and what they are looking for. A great way to connect with the writing community in general.
Awesome Articles
If you have come across other fantastic resources, please comment below!