Posted by Author and illustrator websites are a treasure trove of information. If you like a specific book, check that creator’s website. They may have a blog, FAQ, or even activity sheets/templates for kidlit creators.
Debbie Ridpath Ohi is an author & illustrator, who has an incredibly iconic art style. She does so much with crayons. Check out her FAQs for industry tips.
https://www.debbieohi.com/debbie-faq/getting-into-the-business/