You need to know a niche before you try and fit into it.
As I tell people all the time, if you are going to do something (like you are looking to do) you should pick something of your own personal interest.. feet, legs, goth, bdsm, etc, etc.
Since you have your own preference for it, you know what you like, and most likely what others would like, buy, and so on. It's not just throwing some pretty face in front of a camera, and doing some 'niche' or labeling it as such (like Vivid does on their videos).
The secret to the success of it comes from being able to KNOW the market well enough it shows, and you stand apart from others.
