Hi there!
When I first started, I started with K**n... because it was new and that's where every one was
I now have listings on both K**n and livep***, and have them linked to my personal website. I have biz cards that I printed up at vistaprint (on one of their freebie specials.) and get work that way.
It's not an easy job. It can be physically and emotionally draining. Never ever have I worked more than 3ish hours a day. (I'm good for maybe 3 to 5 readings a day, and then I just need to REST.) But, if you find some balance, and are consistent, you can build a very nice client base and do quite well.
I would say build a page where you are most comfortable, put your own ads out there, and anyone who randomly finds you on the system is a bonus