I managed to NOT win this game!

https://www.chess.com/analysis/game/live/85601947979?tab=analysis 

Any suggestions on how I can improve my endgames like this (or games in general) would be greatly appreciated. Thanks!

wow that engame was bad for u...but you managed to stalemate, also you can check chess.com lessons

You must know that, in King and Pawn endgames, the King has to escort the pawn. Learn about opposition, the square and the concepts of the endgame and practice.

I think you should train more tactic. In a beginner level (like me) I have started to improve a lot as a chess player just by doing some chess puzzles and then playing some games. Finals and openings should be studied later. But you did a very good game

If the opponent's king is behind your pawn - push it. In 32nd move you just could push the b pawn and you could easily win that position because opponent is too slow. Anyways, opening and middlegame was great.

he didn't "manage to stalemate" He unfortunately stalemated. I guarantee your opponent had no intention of stalemating you so dont think that he just outplayed you. He just got lucky. You just needed to know when to sack that pawn, which in my opinion, you did at the wrong time.

Move 33 Nc6 was one good mistake in the game that gave up a lot of your advantage and you played that move in 3 seconds. One Endgame tip: Once the opponent's king is behind your pawn, just push the pawn, the King will not be on time to catch that pawn. 
There is temptation to move fast especially when we have good material advantage. Try to forget about your winning advantage and spend some time to calculate your moves before making them.