Why the endgame is important
I know that this advice (to study the endgame) is very common, and has probably been covered comprehensively many times elsewhere, but I wanted to share some things I've learned on the subject, mostly for newer players who go "Why bother?"
When I first started playing I began by pretty much memorizing openings that interested me, and also the "rules of thumb" for opening and middle game play. This allowed me to beat people who played moves totally randomly and I felt pretty satisfied. Once the opening was over though, I would start to lose patience and get bored, thinking the game was entirely decided by which side has more material (often if I lost a piece, or even a pawn or two I would instantly resign).
Only recently when I made myself try and focus on the endgame (very tedious at first), did I realize how much of a gap there was in my understanding. People often associate "positional" play as an aspect mainly of the middle game, yet nothing shows you the power of piece position more clear and strong than simply playing out a king and pawn vs king ending. You will see that if your king is just one square off it's optimum place, you will lose, if it's one square over you draw. Same goes for deciding if you win or merely draw.
In the middle and opening there is so much "grey" area... a lot of moves are a matter of preference or more acurately judgement, and when you learn any activity, "good judgement" is usually something you acquire only when you're quite experienced and masterful. In the endgame, there is no way to cover up sloppiness and weaknesses in your play because everything is laid bare. So this gives you great insight into the heart of your game, as the importance and effect of every single move is very evident.
It can be intimidating to look at all the incredible amounts of literature on the endgame. I would suggest you either look up online, or in a book, how to properly play a one pawn endgame from both sides. Learn how, then play it out by yourself putting the pieces in different starting positions. It might take like an hour, but see if it makes you think any differently when you play full games again. At the very least it won't hurt, but hopefully you might reap some reward from it (it is very satisfying especially when you see such a simple study earn you a win, or draw when before you might have despaired that all was lost). It is hard to get motivated to learn the endgame (it was and still is for me anyway), but I strongly urge you to give it a try.
