Every organisation has different objectives, therefore, there isn't one, single copy-paste recipe for effective communication strategy.
Creating one isn't a scientific project. I would compare it to an artwork and there are various ways in approach.
The more research you do, before drafting the plan for your brand, the better and there are no shortcuts here. The average time required for such research is around 3/4 of the overall time you may need to spend on the work itself.