Projects are made by people for people!
Who will be affected by or able to influence  your project and/ or the project deliverable? What can you do to get these people involved in the project? What organisational aspects do you have to consider?
Put the people or groups of people in a portfolio.
The two axes of the portfolio represent level affected and influence.
WHICH MEASURES HAVE TO BE DEFINED?¶
You define the measures for the organisation of/ communications to the stakeholders.
Get them closely involved in the project (e.g. as core project team members).
It may be a good idea to make a person a member of an consultant panel or advisory board. Whatever their role in the project, the people in these quadrants have to be regularly and proactively involved in the communication process.
It is often sufficient to provide summarised information on a situational basis.