Help group members learn to reach collaborative decisions through role-playing activities. For one activity, divide the group into two teams and give them a touchy decision to make; each team will argue one side of the issue. Ask one member of the group to be the moderator. Have each member of the teams express her opinion while the others listen. Have the moderator ask the teams to switch roles and take the opposing point of view. Then ask the group to resolve the issue collaboratively. Because each person has argued both sides of the issue, the group should be open to all ideas. This teaches the skills of understanding the entire scope of an issue and decision making through collaboration.
It's common for a few people in a group to dominate the discussion. Assertiveness training can help introverted members to speak up. In an assertiveness training activity, group members are given phrases that they can use to interrupt an ongoing conversation, such as "To build on Tom's point" or "I have a different take on that." Ask group members to pull in individuals who haven't spoken up. Have the leader of the group start a discussion and ask each member of the group to state his opinion. Coach the dominant group members to take a step back and the more reticent members to assert themselves.
Collaboration improves group communication over time. Managers can initiate team collaboration activities periodically to provide groups with opportunities to develop their communication skills. Ask the group to participate in a joint non-work activity such as planning a group recreational event or volunteering to paint a homeless shelter. The goal is for the team to collaborate on an activity unrelated to their work deliverables.
People can become more aware of their body language through non-verbal communication activities. Ask members of the group to write a wordless short play and role-play the parts through miming. Have members switch parts and role-play different roles in one session. This helps the group become more aware of how people communicate, without speaking, in subtle and overt ways.