Patrick Lencioni in his book The 5 Dysfunctions of a Team describes the elements of a great team:

• Trust forms the foundation upon which everything else is built.  If each team member does not deeply trust the other then the rest of the pyramid is weak.  
• Constructive Conflict is crucial for success in business and on projects.  Teams will not be open about problems or engage in active discussions if they don’t have a foundation of trust.  
• Commitment is something that is talked about a lot but without the foundation of Trust and then going through the process of Constructive Conflict team members often passively commit.  
• Accountability to each other and the commitment to hold each other accountable for behaviors and actions that help meet the commitments.  Again; this is often focused on but without the foundational layers true accountability does not exist.  

  > Results is what everyone is looking for but a myopic focus on results won’t make them happen.  Teams must build the strong foundation that makes the top-out of the building possible.  

Going further - Extreme Teams