From a winning position to a Stalemate

I know that many players in the history of Chess would have faced the same problem (including me). And today I am going to help many beginners, and some advanced players fix this issue.

First of all, when you are in a winning position, do not slack and lose focus. For example, in this game, Black was in a winning position, but Black slacked and didn't review the board. A few tips will be available on this study.

The links of the game (media)
Game Study - ChessMedia
stalemategamegif.gif (720×840) (w3spaces.com)
Game PGN - ChessMedia
FEN - 6k1/ppr3p1/4P1p1/7p/8/8/5K2/8 b - - 1 48