This question seems right up Spongey's alley.
I've seen mostly praise for Silman's endgame book.
I played the against strong engines K+8P vs K+8P (king and pawns on the initial position) until I drew with black and white.
Then I played K+8P vs K+7P (took one black pawn, every game from a different column) until I won with white at least once from each of the eight positions.
This is not really practical (pawn endings from real games are seldom so crowded and closed), but I think it helped me.
Then I tried K+B+8P vs K+B+7P, opposite coloured bishops; and I had the task of drawing with black. I drew some and lost many.
I have not continued due to lack of time; but I think you can practice many endgames in a similar way.
I'm currently working my way through Silman's Complete Endgame Course. I'm USCF Class B but have been away from the game for 15+ years. Even when I was active, I didn't have a good foundation in the fundamentals. For example, I don't know how to play the Philidor and Lucena positions, that's how wide the gaps in my knowledge are.
Now that I'm returning to the game, I thought it best to rebuild from scratch. Right now, I'm working on Part Three - Endgames for Class "D". I like Silman's presentation. Once you master the endgame, even just the basics, you will start playing the middlegame differently, ie if you see an opportunity to simplify and steer into an endgame that you're familiar with, you'll choose that route.
I think the key to studying any chess book is to not rush it. I think people tend to rush through chess books so as to feel good about actually completing a chess book cover to cover. But the best way to learn is to break out the chessboard and pieces, set up the positions, then play through all of the variations and try to understand the analysis. For games with lots of variations where it's easy to forget what the node position is before variations start branching off, a computer program might be a more efficient way.
Learn your cognitive load for each day and even each week. Be sure to play live games and not just study all the time. Practice will show you weak points and highlight what you learn. Find a balance and you will improve well. You can even see if there is an ending similar to one you just played which will bump you around your books and make the learning more meaningful.
I went through Silman's book twice and have some others as well and I can say that my endgame technique is above average for my rating.
Going through the small Averbakh, Silman, Euwe, Dvoretsky (not all) I would recommend Jesus de la Villa "100 Endgames You Must Know". I've bought the app version which has also an engine embedded and you can run through the book easily. From all the books I went through I've profited most from this one. And if I could keep only one of them it would be this one. Silman is not that condensed and it is lacking some important details, And although I liked it when I purchased it I wouldn't buy it again. Dvoretsky is just too much for a focused training although he has colored the more important endings in blue to cut down volume for amateurs.
One other which I enjoyed a lot - but this is not real endgame: Benjamin "Liquidation on the Chess Board" on how to simplify to a pawn ending.
One more thing I encounter the most is the question in which way to exchange towards the endgame (with minor pieces). Means heavy pieces may go and then to evaluate your chances with e.g. Knight vs. bad/good bishop, knight vs. knight etc. Interestingly I've learned that from Kmoch when he is talking about "leucopenia" and other weird wordings but the essence is true and saved already some points for me.
According to my own experience, a player improves his chess skills studying actively good books. With "actively" I mean that you will improve just when you invest a lot of effort and time to analise, understand, calculate and find the strongest moves of all the main positions that arises on the board by yourself, before the author gives you all the clues and solutions. So, stop using chess programs and sites. Start to study hard and deeply by good books with real chess board and pieces.
Actually I know a little bit of endings, I know more "general chess", but I'm planning to study the Fundamental Chess Endings (Müller and Lamprecht) as my first endgame book, and in the future, Dvoretsky's Endgame Manual (Dvoretsky). I recommend the same thing I did and also what I am going to do: be good at "general chess", than study a good chess book on basic endings, and finally, study the Dvoretsky's book. I think this is basic if you want to improve seriously your endgame technique.
"... before discussing the specifics of Dvoretsky's Endgame Manual [henceforth 'DEM'], a word of warning is in order. I must emphasize that this is a terribly advanced work that I don't think is a very good way for the average player to study the endgame. The majority of the examples are complex and position-specific, and neither the average student nor even strong masters will follow or play over most of the hundreds of positions that are given extensive analysis, not to mention the subvariations derived from those positions. Even when introducing 'the basics', Dvoretsky's approach is often more complex than is necessary for an average student, and in any case such a thick book will seldom be used for the sake of elementary instruction. The majority of the other material is frankly very difficult. So take note: I don't want to be blamed, in praising this book, for your purchasing something that you find intimidating, relatively dull, or otherwise unsatisfying. That said, if you are up to a real challenge and have a great deal of time to devote to reading and playing over examples you will inevitably derive great value from this work. ..." - IM John Watson (2005)
http://theweekinchess.com/john-watson-reviews/the-end-game-comes-before-we-know-it
https://web.archive.org/web/20140708233815/http://www.chesscafe.com/text/review399.pdf
http://www.jeremysilman.com/shop/pc/Dvoretskys-Endgame-Manual-3rd-Edition-78p3502.htm
https://www.newinchess.com/media/wysiwyg/product_pdf/2703.pdf
I really like chessable as well. The Basic Endgames course is very good and its completely free to use. I would like to get the 100 Endgames You Must Know book too. That one is 20 dollars but I think it would be well worth it.
Resource recommendations are always welcome, of course, but how does one go about trying to make best use of these many possible resources for a successful long-term systematic endgame study plan, as recommended by many strong players and trainers (Tarrasch, Capa, Averbakh, Karpov, etc)