Staunton made up for his relatively late discovery of the game with a tremendous zeal for theory. He became the most knowledgeable opening theorist of the day. He also familiarized himself with positional concepts in the middlegame.
This was a remarkable feat as the material to learn such things were thin on the ground. Everyone was simply putting combinations together and little was known or appreciated of things like pawn centers, pawn breaks, fianchettoed Bishops, playing for space advantages and more active pieces and so on.
Staunton's understanding of the elements of positional play was on a par with top level chess a century later and even today. It was these things that enabled the late starter Howard Staunton to become the best player in London. This is why Bobby Fischer would later say:
Staunton was the most profound opening analyst of all time. He was more theorist than player, but nonetheless he was the strongest player of his day. In addition, he understood all of the positional concepts which modern players hold dear, and thus, with Steinitz, must be considered the first modern player.