Before I give students a group task, I discuss with them issues likely to arise in doing group work as well as how to manage the group task.
The discussion includes consideration of:
(i) skills of each group member;
(ii) time constraints and availability of each student;
(iii) interests of each group member;
(iv) which model of group work to use?- either the leader sets tasks or each member contributes equally to the process;  
Students are given templates to survey each of (i) to (iv).
(v) Students arrange a time line for project.

Student progress meetings are held to discuss where each student is with respect to task assigned and students fill in a milestones template at that point. Points are given for carrying out the group process.

The templates used are adapted from: Caspersz, D., Skene, J. & Wu, M. (2006).  Managing student teams. Milperra, NSW: Higher Education Research and Development Society of Australasia Inc. (HERDSA).