Having a marketing strategy means understanding why you're different from your competitors. It means deciding what direction to take the business in, once you've clearly identified your brand and done your research. It simply means knowing what you're setting out to achieve. 

It can be as simple as a couple of sentences once you have it figured out. You may just hold it in your head. But what it does give you, is the ability to prepare a proper marketing plan, because once you know what your goals are, the planning part is much easier.