Unique content is your secret ingredient
There were few ways of promotion for a photographer whose career evolved during the first decades after the advent of Internet (and, consequently, the development of social networks). All types of marketing and advertising used to be quite aggressive back then. Nowadays you no longer have to scare your potential clients away by popups and bulk email; quite recently the Internet has witnessed the advent of a promotional tool which is called content marketing. By the way, it is still relatively new for the Runet.