Communication needs to be continuous, open, and focused on identifying barriers to progress and solving problems. Your expectations about participation in project meetings, reviews, management presentations, etc. If you schedule project team meetings on a regular basis, you need to let people know if their participation is expected or optional. The same applies to reviews and management presentations. How conflicts will be managed and problems solved.
Conflict is inevitable on most projects.
How it is managed makes all the difference. Explain how you plan to manage conflicting demands on participant's time, conflicting priorities, technical differences, etc. Review the informational and updating processes you plan to use. Explain what you expect as content for status reports. Explain how you will keep the team informed about progress, problems, successes, etc.