Continuing the discussion from How do you do books:
I’ve acquired enough ebooks that it’s getting hard to find them. How can one organize one’s Kindle library?
I tend to think in categories, with a series or universe with derivative works also in my collection getting its own category. Then I have sections for cooking, organizing (smile), time-travel fiction (I have a fair amount of that), religious, movie novelizations, dystopian, mystery, true crime, stuff borrowed from Kindle Unlimited, general fiction, and stuff I haven’t sorted yet.
I didn’t mean, what categories do you use (although that’s interesting, too), but mechanically, how do you organize books on a Kindle.
Sorry, I had just gotten up. 
You’d use the Collections view, create your collection of choice, then go through and select books and add them to it. Repeat as desired. I use the Kindle app on an Android tablet, so can’t give step-by-step since the interface is probably different on a stand-alone Kindle.
For fiction, I make collections for each author that I have more than six of their books in my collection. I then organize them based on what makes the most sense for each particular author. Some are by date published, others by their most well known works first, then by date published, still others by short story collections and then novels (or the other way around), and so on. It just depends on what each individual author has written. For non-fiction, I divide it by category and then organize the books in each category alphabetically.
This. It’s a lot easier to organize them on a device using a Kindle app rather than on an actual Kindle. The actual Kindle has no options for organizing things book by book, with a different strategy for each separate author. It has to be the same way for your entire collection, and it sill sometimes messes up. I’ve posted about this before, but I’ll repeat this anecdote because Amazon still hasn’t found a way to fix this. For my collection of Sue Grafton books, A is for Alibi is alphabetized between I is for Innocent and J is for Judgment, because the algorithm seems to thing the correct title for the book is Is for Alibi, A. On the Kindle app it’s as easy as clicking and dragging the titles to organize them.
I also wanted to add another dig (and rule out another option) - the Kindle cloud reader (if you want to read from a web browser on your desktop or laptop) is similarly useless.
The sort features are pathetic, no way to create new collections, or otherwise add much organization. Just by author, by title, or purchase order. One tiny exception to my hate for this version is the ability to pull up any highlights you have. This is a fast way to clear any you made by mistake, or to copy out from the browser if you even want to quote a selection to a fellow fan, or to have a zippy quote for a post.