Teams initially go through a phase in which members get to know one another and then try to define the team's goals. Once they establish these goals and everyone understands them, the members go through a period of conflict where they try to identify their individual roles within the team. The leader's job is to guide them through those phases so they can reach the last phase and become a single, cohesive team.
The two most commonly used models for team development are Tuckman's model and COG's Ladder. Both start with the dynamics of getting to know one another. Team members use this phase to get to know the basic facts about their new teammates without getting too controversial. This is why George Charrier, who developed the COG's Ladder model, called it the "polite" stage. Icebreakers are the best type of exercise to move people through this stage, especially ones that require individuals to disclose personal information, such as their most embarrassing moment or their personal life goals. For a large group with both veterans and newcomers, designate one veteran to be a "mystery person" who gives out a prize to people who introduce themselves. This encourages new members to become a part of the team rather than an outsider watching what the group is doing. The dynamics at this stage are simple. People need to believe they are part of the team, and social interaction with other team members is the best way to get them through this stage.
The next stage deals with defining group goals. Charrier called it the "Why are we here?" stage, but Tuckman included it as part of the first, or "forming stage" of his model. Sometimes teams receive their goals from a leader outside the team, in which case this stage is very simple and improving dynamics through it is unnecessary. Sometimes, however, a team will only have a high-level objective and must define its own goals to reach that objective. Cohesiveness is not yet part of the dynamics, so this is the stage where unproductive conflict can begin. Exercises that enhance communication skills are vital at this point, as are exercises in conflict resolution. These are the primary skills individuals will need to move the team forward. Goal-setting exercises are useful as "practice runs" for the goal-setting they will ultimately perform with the team.
If conflict didn't enter into the team dynamic before, it will in this stage. Tuckman labeled it the "storming" stage, while Charrier called it the "bid for power." In this stage, individuals fight for a place or role in the team. If your team is a group of specialists, this phase goes a little more easily, but when people with multiple talents all want the same roles, conflict will ensue. The conflict-resolution exercises started in the previous stage should be continued. Team problem-solving exercises that force people into various roles are also important. This gives members the opportunity to "test drive" a team role before deciding whether to pursue it. It also gives them the opportunity to see how other members handle different roles and may lead them to give up roles they would have otherwise sought. Exercises in self-evaluation and evaluation of others are necessary at this stage as well.
Once individuals settle into their roles within the team, a transformation in the team dynamic takes place. Conflict gives way to cohesiveness and constructive criticism. Team members begin to follow a set of unwritten norms in addition to those that are formally stated. Tuckman called this the "norming" stage and Charrier called it the "constructive stage." Exercises at this stage should improve the team's overall ability rather than improving the dynamics within the team.
Very few teams reach the highest level of performance, which Charrier called the "esprit" stage and which the Tuckman model describes in the upper echelons of the "performing" stage. One of the most famous teams to reach this pinnacle of performance was the 1980 U.S. Men's Olympic Hockey team. A team at this level does not need exercises to improve because the improvement will come from within. It is part of the dynamic and definition of a team of this caliber. The only time exercises are necessary is if a new member joins the team. Those exercises should focus solely on bringing the new member or members up the current level of the team.