Offline. it's usually straightforward
Sometimes locating your target market is not as straightforward. For example, I have done some distribution of takeaway menus for an Indian restaurant in North Perth. Interestingly the best response was not from the houses close to the venue, but from unit rich areas further north like Yokine and Joondanna.
I think this had much to do with the ethnic and age demographics of each area. North Perth has many older families and empty nesters and there are quite a few people from southern Europe. Further north you have more young and single people, with a more diverse ethnic mix.
Online, it tends to be more involved
Finding your target market online is often a bit more complicated than offline. Take social networks. With these, sometimes you have to some snooping around and use some trial and error. But not unlike offline, you can often find concentrated clusters of people to market to.
Another personal example: Having written and performed a lot of comedy in the past I've accumulated many insights and tips that can be of use to comedians. So I've built a site, with blog, for this content. I've got some links to related affiliate programs on it, and one day might get around to writing an ebook on the subject that I can sell off the site.
Being talkative and somewhat self-obsessed types, comics have taken to social networking with gusto. And they absolutely love Twitter. It's pretty obvious why. They can hone their one liners on there; post funny selfies and gig photos; promote upcoming performances. And they seem to interact a lot with other comics. Often at least half of the tweeps a comic follows are standups just like him!
They do this on Facebook, too. But they seem to use this site more for interaction with fans as well as for pure promotion. It's like a press release site for them -- a place to post details of upcoming shows, etc. Because of this distinction, I'm putting much more effort into Twitter, at least for now ...
The takeaway lesson: When looking for your target market on social media think about who you're trying to reach. Ask yourself what qualities they have and where they're most likely to be. Then go looking there. Your hunch may be right. But if it isn't you'll soon become wise to this and find them elsewhere.