My current rating on chess.com is 1813, and like everyone else, I want to live to the next century. It occurred to me that if I want to play at the 1900 level, ie win some games at that level, then I should see what is involved. Accordingly, I had a look at some high-rated games and sought for the critical moment in each game, ie the point at which the game was won. My theory is that many games hinge on a single move, ie a mistake by the losing side.
The first diagram shows the position just before Black's 37th move. I believe this is the move that decided the outcome. Black is about to play 37.... Re8 and probably does not expect White's reply. Note that White has an extra passed pawn and that his pieces are more active, but how would you exploit this advantage?
The game continued
38 g4+ Bxg4 As the bishop is lost anyway if the king moves back.
39 hxg4+ Kg6
40 Bd6 Nxd6 Hoping to equalise material.
41 exd6 Rxe2
Black resigned, as the pawn cannot be stopped after 42… Rd2 43 Rd3.
Source: game 1
In the second position, White is just about to play 13 c3, little realising that the continuation costs him a piece:
Source: game 2
I guess there is not a lot to be learned from these two games, except that even highly rated players make blunders. You are not alone!