This topic is very interesting...from my experience i can clearly say that this law does not function simply as to just think about something and getting the results wanted.I mean maybe it works for others, but for me its a bit different.
I think that the secret described in the documentary ''the secret'' is a disinformation about this law.
For me its quite complicated...the less i think about something the more its going to happen.Example:i was thinking way too much about what to do in order to have a girlfriend and every attempt failed, but since i stopped thinking about it so much everything is going way better.What i come up with is this...this law applies when you are on the right path and you can express thought-like energy for a result, but when something is not for you at a point than all the creative energy you sink in it won't do a thing.So this law is very closely tied with ''destinic energy'' as i call it and your inner self in order to know in your heart when you are on the right path or at the right time for something.