Control of the Board
There are sixty-four squares that the player must control. If not, he will loose and a loss of one game can show defeat in a player. That is one lesson that every chess player should know.
Bobby Fischer knew very well how to do that and almost no one could defeat him. He said, "Chess demands total concentration and a love for the game." That's exactly what he had, a love for the game. That's what I believe, that every player should know that they can only be good if you have a love for the game.