The Purdue Online Writing Lab is a lab at Purdue that I have been using for over 20 years as a resource to help my students with writing organization, MLA formatting, citation, and even grammar. This is a youtube channel specific to the lab and writing. These are open and available on youtube.
For example, there is a youtube video on Paragraph Organization and Flow. From the video: In this IWE lecture, Heather from the Writing Lab helps thesis and dissertation writers organize their writing at the paragraph level and addresses the hard-to-define but all-too-important quality of "flow."
These are oriented towards upper level high school students and college/university students.