Insight is the understanding of everything football. For this you must understand how tactics, formations and principles of play shape a game. Once you understand this, you need to understand how they can effect each other and why.
If you are a player playing in a wide position, a defender may need to mark you to prevent the pass, but if he marks you, your team mate can dribble through the space he leaves.
Playing wide to create space is the tactical concept, seeing the defenders dilemma is the insight.