Difficult in that I don't believe in it except in the grossest terms where it's practical. Like, if you're a misery and want to attract easy-going, fun, happiness into your life, you have to get yourself optimistic.

I've given illustrations in this thread and others of why it can't work when it comes to specifics + some discussion here as to why. It isn't a law. It can't predict an outcome even with a moderate probability.

One of the principal instigators of this technique (I'm not allowed to mention names) was shown by adepts to be a fraud. He simply didn't believe what he was expecting others to believe but he has made rather a lot of money from his books.

So answering your question is about as easy as, well, asking "what do you believe a motor car isn't?"