When the Pittsburgh Steelers from the '70s were winning Super Bowls, it was because each team member bought into the fact they would need to change their mindset. They put the team ahead of themselves. They got rid of the "I am going to get mine" attitude and checked their egos at the door. Each player had a sense of pride putting on that Pittsburgh Steelers uniform.
Those players had integrity. They changed their attitude to gratitude for God allowing them to play in the NFL, never taking it for granted, and embraced a synergistic mindset. The team collectively developed a respect for the game and each other.
The word TEAM means (T)ogether (E)veryone (A)chieves (M)ore. It's often been said that "a successful team beats with one heart."
It even has to start with the player personnel staff when drafting or signing free agents. For every player, they need to seek candidates who can work well in a team environment.
The Steelers organization as a whole has to promise to give 110% putting the team above themselves. It's also been said that "there is no traffic on the extra mile."