Hey Martin!
I've found social media to be a very difficult way to sell as the engagement is significantly lower than email, which is a very direct line of approach to your prospects.
I've found email lists to be the king, by far, for selling photography and related services to. But building a list takes effort and it requires that you create real value and then give it away for free, in exchange for an email address, at which point you followup with high quality content (that might ordinarily cost money but you're giving it away) and then things to sell.
At which point you say "Buy this now" and they do.
Graham