How true is self-manifestation and the law of attraction?

I have read how focusing on what you want will get you what you want. The theory is like attracts like. Thoughts become things. Well I’ve also read a counter argument to the law of attraction as taught by the majority of teachers now a day stating that the law of attraction will not work if people use the techniques based on their greed and desire of money, fame, and wealth. Rather the article stated the only way self-manifestation really works if it is is used in a way to help others. I’m curious as to what exactly is your belief regarding this matter.