The first one called '21 dumb mistakes to avoid when writing your first e-book' is a must read. Thankfully the writer has grouped the mistakes under sub headings, and gives both the common mistakes and how to fix or avoid them. http://myexpertdesk.com/21-dumb-mistakes-to-avoid-when-writing-your-first-e-book-2015/?utm_content=buffered7b7&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer The tips I like most are a) writing your introduction when you have finished your manuscript, b) copying your draft before you start making any edits (so you can find the bits you cut out and want back in), and c) proofreading your work in a different format, and font and font size to the one you wrote it in.
The second one is this wonderful set of annotated photographs of an illustrator's process in producing a double page spread for a picture book. http://www.theguardian.com/childrens-books-site/gallery/2015/mar/24/korky-paul-how-to-illustrate-books?utm_content=bufferedef2&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer It takes you on a journey from the text to go on the spread, to the first A4 rough draft and all the way to the final artwork, with notes on paper selection, graphite pencil selection, on what makes a good eraser and other tips. For an author, reading it will help you understand why the artwork takes so long to prepare and costs so much. For an illustrator, there is always something new that can be learned from another professional in the same field.