My research over the last 10 years suggests a three-phased approach works best.
One: Identify the stakeholders and figure out what you need from them and what they want from the success (or failure) of the project. This is called 'mutuality'. If you can show the person they're likely to achieve at least some of their aims, they're far more likely to provide you with what you need from them.
Two: Work out which stakeholder is most important. This requires assessing at least three aspects for each:
• How powerful is the stakeholder? Can he or she close the project down, force change or do they have little direct impact?
• How much effort is the stakeholder likely to invest in asserting their position or 'rights'? Some stakeholders will go to almost any lengths to assert their position while others are really not that interested.
• How close is the stakeholder to the project? People actively working on the project have more impact than those who are relatively distant.
Three: Determine the attitude of each important stakeholder towards the project and how receptive they are to your communication.
Now you have the information needed to focus your communication efforts where they can achieve the greatest benefit. People who have a supportive attitude simply need 'business as usual' communication. On the other hand, important stakeholders who are assessed as having a less than optimal attitude may need heroic communication efforts to change their views if the project is going to succeed.
And always remember: People change. Reassessing the stakeholder community on a regular basis helps ensure the communication plan is working or if it needs changing.