Here's a list of blogs or links or books that are helpful and informative for a writer looking to be the best writer they can be and places to go where they can hone their skills.
Guide To Literary Agents Blog
Society of Children's Book Writer's and Illustrators
Insitute for Writers (I took a class or two here years ago. It's literally what propelled me to keep writing).
On Writing, Stephen King
The Forest for the Trees, Betsy Lerner
Walking on Water, Madeline L'Engle
The First Five Pages, Noah Lukeman
Reading like a Writer, Francine Prose
Robert's Rules of Writing, Robert Masello
A Million Little Ways, Emily P. Freeman