Please don't dismiss word of mouth...my photo business, I think yours, plus many others, will get the majority of work through word of mouth. And keeping that word of mouth going is quite an art, taking as much time and effort as more standard forms of advertising. In the days before social media we called it networking and it worked along side direct mail, advertising, cold calls and portfolio shows.
My old boss used to say 'Contact, Contacts, Contacts... it doesn't matter how you make them just go and make them!' The trick was then to keep and convert them!