Sylvia, like most so-called psychics, is very good at a process called
cold reading. With practice, someone - even me! - can create an aura of psychic behaviour that borders on the spooky. The trick, which obviously Browne hasn't quite mastered, is to stay away from specifics and only speak in generalities.
Of course, this doesn't mean that ALL psychics are using the cold reading technique. There may be something to it, but in Browne's case it's pretty clear that her so-called "powers" leave much to be desired. And for $700 an hour, I'd want pretty hard proof.