That's a 'loaded question' !
Chuckling here...I DO know who my target customer is but getting to them via the internet takes A LOT of work.
When I first started my Photo Greeting Card business, I created an (offsite) email list and I add to it anyone who is even remotely interested in what I am selling or what I am doing; such as a new item or participating in a local craft show.
I post on FB (both personal and business pages), Twitter, Tumblr, Pinterest, Google+ and an occasional blog from my personal website. I do all of this to stay 'relevant' and for exposure. This is how I start every morning (when I have a 'fresh brain') and, yet, my sales through Etsy are very slow.
When people see my products in person, they sell. However, I find it a 'tough go' on the internet.