How does an organisation ensure effective communication with its key stakeholders?

i think to ensure effective communication to all key stakeholders, the responsible authority has to devise a communication plan which addresses all stakeholders. the plan must include questions like,

i) what kind of communication is required for different stakes

ii) who needs to be communicated with

iii) how often and what needs to be communicated

 above all the communication plan has to be adaptable and suitable for the key stakeholders, thus ensuring information is provided in right manner, to the people with the right impact.