I think really knowing your teammate is the most important thing. The relationship between Brook and Claire was one that we usually see on The Amazing Race but it usually does not translate that well. With Brook and Claire, Brook was always pushing Claire to do better and not give up. But she did it in a way that did not berate her teammate. This is not the usually story as we saw this season. Brook never asked more of Claire than she thought Claire could do. But Brook and Claire can communicate pretty well and they know each other very well so when Brook pushes Claire, Claire has her moment and they're back to racing and you don't feel bad about what happened between them.
Then you have racers like Nat and Kat who as they said were co-captains of their team. They were always Nat and Kat. And they mirrored each other more than any other team. This was good for them because they were both pulling equal weight instead of one doing more than the other. They knew what each other needed and didn't need. Nat said when they were doing the bungee jump, Kat knew how to handle her. They just gave you that sense that they were a team, I think more than any other team.
So I think these two teams set the bar on what makes a good team. Either you have that one that leads but knows how to lead without being a dictator or you have the equal team effort with both teammates pulling the same amount of weight. But being able to make good, quick decisions, not quitting, and being respectful are important as well and those should already be in place.