Discussing and writing down why you are doing this in the first place will help you prioritise
Identify who your priority audience is. A campaign trying to speak to multiple audiences risks not connecting with any of them
Ask yourself why hasn’t this audience been persuaded so far? Then identify what you think you need to say to persuade them.
Once you know what to say, then identify where your target audience get their information. Focus on that particular avenue of communication.
Make sure that the principles of how you will execute a communications campaign are agreed by your organisation