Many amateurs agonise over why their chess isn’t better, with most blaming their alleged lack of opening knowledge. In reality, though, chess is really all about calculation. The old question chessplayers always hate being asked by non-players, namely “How many moves do you see ahead?” really is the key point. The biggest difference between strong players and weak ones is the former’s ability to see further, with greater accuracy and faster. Try analysing with a really strong player some time, and you will see what I mean.
The following game is a nice (though difficult!) exercise in calculation. After Black’s 24th move, he is threatening Nf8 and g6, blocking the K-side, so White must act quickly. But how? He needs to attack the h5-pawn, but 25.Ng3 is met by 25…Bg4, whilst moving the Nf3 loses the h4 and g5-pawns.
Stein’s solution involved seeing a bit further. Have a go yourself and see if you can find White’s 25th move. Even if you don’t find it, having seen the answer, put the game aside and try to calculate the consequences. For maximum points, you need to see to move 36 at least, in the main line.