You can metaphorically take a page out of a coloring book, and break up the work into a few sections. Each team member or group within the team should first be instructed on which part of the page they are going to color, let them know what color they can use, and when their turn will come up. Next, after each team member has finished their part of the coloring than take the completed picture and hangs it up so that every one can see their part of the picture and the entire teams contribution.
The lines of your coloring page are the rules you need to share with your team, share with them the boundaries. They are more likely to stay with in the lines if they know that they exist. Next by holding the work up for group and team acceptance they become their own self policing force. They can set self expectations and make constructive self criticism as well. The reward is acceptance and recognition from the team, an old saying is that a person can starve without any feedback, but only needs one good compliment to be filled to overflowing.
When I was a child I just loved to draw and paint but, as I remember, before I even could begin to draw accurately I used to color in. The next stage was to learn to draw using stencils and then I graduated to be able to draw freehand which provided me with an absolutely fantastic sense of achievement. I went on to love drawing but the point I am trying to make is that it all started with the simple yet effective art of coloring in!