52. Kf5
The final position is a won pawn endgame. But if you want to win endgames, you have to study them. There is no substitute.
There are many good introductory books on endings (Pandolfini, Silman, Seirawan). There's also Starting Out: Pawn Endgames by Flear and Secrets of Pawn Endings by Mueller. I publish pawn endgame articles. Perhaps some of these will help you.
Thanks likeforests. I just purchase
Fundamental Chess Endings-----Karsten Muller & Frank Lamprecht
Mastering the Endgame------Glenn Flear
Chess Endings------Yun Averbakh
Capablanca's Best Chess Ending------Irving Chernev
Understanding Pawn Play in Chess------Drazen Marovic
Kf5 kicks the king out from the square in front of the pawn. If your king can occupy that square you have a queen.
About the chess books, you can only read one at a time.
Sitouation can be solved in many ways so I just give another.
Apart from 52. Kf5 it is also possible to win by playing in the move 53.Kf8
instead of going back (Ke6 as in the game) after 53. Kf8 your opponent has two
legal moves Kh7 and Kf5
after 53. ...Kh7 54. Kf7 wins black's pawn
and after 53. ...Kf5 54. Kf7 secures a clear path for the g-pawn
Here is a game which I played on Yahoo. The time limit was 10 minutes for each player. This game I felt I was winning at first, then the game shift after move 17. However, I believe I still had winning chance, but my knowledge of endgame ending is lacking. So here we go!