Marketing is often something photographers are struggling with, because they usually focus more on the artistic and photographic skills to develop and grow in. But we all got to live and pay for our groceries, so some money needs to come in as well.
There are great marketing blogs to help understanding how marketing works, like the Hubspot blog, but this is a general blog for marketers and not specific for photographers. A very good source of knowledge and advice for photographers are the Photoshelter Free Guides on a wide range of marketing and business subjects especially for the photographer’s needs. They translated the general marketing tools into photography specific tools, suiting the small size photography business as well.