I'm using FB for marketing more of what I am known for... helpful links and niceties. Feel free to see what we do with it.
I like it. It keeps our clients updated. I mainly use it if I have something that may have changed with the office (times availiable, open appts., etc.)
and things (usually links)
I want to share. I try to keep it pretty light and easy. Not too many politics or "selling". Every once in a while I'll suggest that someone "like" our page, write a review, read a review, or consider buying a gift certificate.
I have found that our clients like the FB page, and even though they don't respond often, they do read it. When I post my remaining appointments for a week, I will generally fill a few. Sometimes people will remark they want an appointment on the page itself, but they know they still have to call to actually "get" the appointment.
Hope this helps.