This way of thinking has been promoted for a while but there is still a large amount of people who have tried it and cannot get it to work in their favor. I'm sure even those who believe it has worked at one point or another in their lives would admit that it doesn't work more than it works.
I would recommend anyone who has felt this way to look into the Human Design system. It explains that there are 5 types of basic profiles that everyone falls into and only 1 type (about 10% of the population) has the ability to truly manifest as books like the Secret have talked about. There are various ways others can manipulate the system to attract things in a roundabout way but it's not their default.
I know this information will come as a surprise and many will actually push it away as they may love to believe that they can manifest and would not want to entertain the possibility that it doesn't exist for them. Either way, looking into the Human Design system is worth it.
Knowledge is power but Wisdom is in the emptying.
For someone to accept the LOA, they have to be ready and want it entirely. An everyday example of the law of attraction at work is this;
It all starts with a thought then you have to BELIEVE you want it and can have it, then you take ACTION, then you RECEIVE!
That's a basic example, but it can be used for other things as well. It is just your subconscious mind feeling a need for something and it won't stop planning and doing until you have it. But you need to convince yourself that what you want is obtainable and through enough time and effort you will get it.
Some people refuse this and say it doesn't work because they went in with a closed mind and thought "I want a million dollars" and if a million dollars doesn't spawn at their doorstep then they instantly reject the idea and forever stay closed minded about the power of their thoughts.
I'll read up on the Human Design System, thanks for commenting @veritees !