A team charter can help focus on your purpose. In your team charter, include the overall purpose of the team, your key customers, the key results areas, your guiding principles, and milestones.
If you are a team leader, spend some time brainstorming about your team charter before you present it to your team.
Because charter making will require an hour or two, some members who are “busy” with work resist doing this activity. Study how you can communicate the benefits of having a team charter to your team. They need to own your team charter for it to be truly useful.