In short, start with the business objectives, then how marketing will contribute to the business goals, then how will the marketing department and efforts support those, short and long term.
Too many companies start tactics, but don't do the required preliminary steps:
I'll hear companies say their strategy is to "rebuild their website" or to "do social media." These are tactics, not strategy. And without a defined strategy that is tied to the business objectives, you are wasting time, money, energy and consumer attention.
While I'm not advocating waiting until things are perfect, I do stress that there needs to be clear communication and coordination to ensure that the marketing department is doing intentional work that will move the business forward, rather than random activity that just demonstrates being busy.