I believe the Law of Attraction comes from the book The Secret which was a very popular self help book that focused a lot on how to attract money to your life among other things.
I believe there are references to it on one of their blogs
Hi, Human. The Law of Attraction has a long history dating back to the late nineteenth century. In our time, The Secret certainly popularized it.
Jodi seemed to view it as a kind of justification of destiny.
P.S. A completely unrelated aside: In the recent Arias interview mentioned previously here, she mentions that she was disciplined for hiding pens while incarcerated. It occurs to me that Jodi might have used these instruments to concoct her Travis "I am a deviant" forgery. It exists only as a photocopy (probably smuggled out of prison), but even such a derivative copy could be easily identified as having been written in (jailhouse permissible) pencil or (outlawed) pen.