You can spend a lifetime of study just mastering the End Game, it isn't something you can pick up with just a few quick tips (trust me, I've been playing chess for over 30 years and used to play at the 1600-1700 level when I played actively and End Game is still a total mystery to me).
How can I improve my endgame technique?

Grrr...hate when my post gets cut off and posts prematurely. Best I can suggest is to either find a coach (best) or get your hands on an End Game book or online lesson and spend a LOT of time studying it. It's probably the hardest aspect of the game to study, but being competent in the End Game is highly rewarding.

It's vital to first learn basic endings. This would be roughly the first 4 parts (through Class C) of "Silman's Complete Endgame Course", which is highly recommended. It would help to keep going through Silman, but for strategy and planning in more complex positions, Karsten Müller's "How to Play Chess Endgames" is a real gem.
Some people will recommend Shereshevsy and Dvoretsky. Their endgame books are great, but they are aimed at an audience a good bit stronger than us. Once you grasp the material in Silman and Müller, they would be the next step in mastering the endgame.
My recommendation would be to study the simplest endgames first. The more of these endgames you know how to win (or hold the draw), the easier it will be to convert a complex endgame into a simple one you know.
The other two main points are (1) piece activity is usually worth a whole pawn, and (2) king activity decides most materially-level endgames. Rooks on open files, bishops on long, open diagonals, and central knights on outpost squares are easily worth as much as an extra pawn. And a player who activates the king just two moves earlier than the opponent going into the endgame wins almost all of the time, because the player who tries to keep the king "safe" into the endgame is basically down a piece. Rooks on open files, bishops on long, open diagonals, and central knights on outpost squares
i'm in the same boat, i get crushed in the end game and i think it's because i don't really have any good strategies to throw at the board. i'm always being too aggressive when i should be defending my pieces, or being too conservative when i should be attacking.
will check out this silman course!
Overall, I think: study Averbakh's thin book and Chernev's book & you'll play endings better than most 1800's.
My own 'chaotic plan' has been this:
Got some thin, 100 page, books on endings & work thru them when I travel. [Not sure I really need more than Averbakh's 'Chess Endings: Essential Knowledge' but I have a few.]
Study endgame strategy. I've been thru Chernev's book on Capablanca's greatest endings [a terrific book], Shereshevsy's 'Endgame strategy' and Reinfeld little but excellent book 'Reinfeld on the Endgame'. The last 2 are organized by theme. All 3 are very good and Chernev's book s great.
Then I have the thick books of Dvorevsky and Flear's ' Practical Endgame Play'. When I get an endgame in one of my games I look up similar ones after the fact and study the similar ones. It is easier when you've just misplayed one.
I've also studied especially endings arising from openings I play by looking thru annotated games.
I also find videos here to be very good because you can test what you just saw right away.
-Bill
ps-- Recently discovered the books of Mednis on endings. These are also very good.

I have about 40 endgame books. Dvoretsky has been the most useful to me, while I find Silman's overrated. Most people find that Silman's works well for them, so who am I to criticize that choice.
Averbakh, Chess Endings: Essential Knowledge, which I recommended earlier is this thread, is excellent, as is Chernev's book on Capablanca.
Most of mine:
I have about 40 endgame books. Dvoretsky has been the most useful to me, while I find Silman's overrated. Most people find that Silman's works well for them, so who am I to criticize that choice.
Averbakh, Chess Endings: Essential Knowledge, which I recommended earlier is this thread, is excellent, as is Chernev's book on Capablanca.
Most of mine:
How do you find the book 'tactical training in the endgame'??
I also find Dvoretsky really helpful. He has a style of explanation that makes the key ideas stick in my head. (I have an overlap of 10 endgame books with your shelf!)
-Bill

I have about 40 endgame books. Dvoretsky has been the most useful to me, while I find Silman's overrated. Most people find that Silman's works well for them, so who am I to criticize that choice.
Averbakh, Chess Endings: Essential Knowledge, which I recommended earlier is this thread, is excellent, as is Chernev's book on Capablanca.
Most of mine:
How do you find the book 'tactical training in the endgame'??
I also find Dvoretsky really helpful. He has a style of explanation that makes the key ideas stick in my head. (I have an overlap of 10 endgame books with your shelf!)
-Bill
I like it. I've only used it a little bit. I've used his Tactical Training more and bought the endgame book when it came out so I would have the pair. The positions I've looked at are well-chosen and instructive.
I know it is necessary to study theoretical ideas and positions, but I feel like I struggle most with endgames which have multiple pawns and pieces still on the board. Basically, practical endgame positions which must be simplified down into the positions that I study are confusing for me. For example, in an endgame where both sides have 2 rooks and a minor piece each, with a handful of pawns where one side has more pawns with better structure than the other, is not something I would study specifically, but it is how endgames begin. How can I work on my endgame technique? What endgames are must-knows for someone at my elo level? Thank you.