The concept has been around and accepted for centuries. The idea that what you focus your thoughts on will eventually become a reality in your life. Some call it manifestation, some call it the law of attraction, I call it focused observation.
In reality, it doesn't matter which angle you look at this from. Pick a theory that works for you and go with it. The basis is the same ... Your will find what you are focused on!
We have been doing it since we were kids. Just follow the instructions in this picture to see how it works.
At first it just looks like a normal picture right? Then you find the objects, that might take a minute or two. But after that the objects just jump out of the picture and look really out of place! Why the heck is the dog's bed leaning against that tree? He can't lay in that. Poor puppy.
Go for two walks in the woods. The first time, just walk and enjoy the scenery. the second time look for mushrooms. Guess which trip you will see more mushrooms on. Yup, the second one. Why? Did the mushrooms magically appear on the second walk? Of course not, you were just paying attention to them. Things tend to blend in until we are actively looking for them.
We see what we are looking for. Once something is top of mind, we will be more observant of it.
This is the same in all aspects of your life. If you go through life always afraid of things, you will see all sorts of things to be afraid of. (That is why your basement is creepier after you watch a horror movie). If you go through life paying attention to the good things around you, you will see all sorts of good things to be thankful for. If you go through life believing you are a failure, you will find ways to fail. If you go through life believing you will be a success, you will see opportunities to succeed.
Decide what you want to look for. All the opportunities will be there in your path, it is a matter of looking for them so that when you are close, you actually see it.