I'm a psychology student, so I'm confronted with all kindS of theories every day and I also learn how to decide if a theory is good or not that good. I don't know, if it even makes sense to discuss a theory within the system it is working in, but I will share my thoughts anyway.

I'm on that journey for a while now. In the beginning, I had a poor understanding of LoA, but even after I felt that I got it fully, my view on it changed and evolved. In the beginning, there is so much stuff you hear about: Feeling good, acting as if, meditating, scripting, ignoring reality. You most probably don't see how this all fits together perfectly and how it is the practical application of one simple theory. Most people make it more complicated than it has to be and even invent new concepts to explain things that they seemingly can't explain with the basic LoA principle.

What is the basis of LoA?
You create your reality and you do it with your thoughts, beliefs and expectations, period. That's it in my opinion and in my experience. There is nothing else than this principle. You can explain everything with it and that's btw one important criterion for a good theory.

You may say now "But today, this bad thing happened to me and I haven't thought it would happen". Maybe your car broke down or a dog attacked you and you haven't thought about that. So it wasn't something that you thought about. It wasn't probably something you believe happens to you all the time. But did you expect it in a way? Do you think it's possible that your car will break down one day? Is it in the range of the thinkable that a dog would chase you? Do you think there is a probability that this could happen to you? There you have it. That's the reason why it could happen to you. You have beliefs about how likely it is that something happens and LoA has to match that beliefs. So, nothing is random. You create all of it. You create the tree, because you know that there are trees in your world and you expect them to be there. You create me, because you know that you aren't alone on this planet and you let me act in certain ways you think are likely. Sometimes I do things you don't expect, because you believe that my behaviour is kinda random and you can't foresee what I'm going to do next. Looking at LoA in this way, you suddenly can find an explanation for every situation.

Other important factors for a good theory are

1) Can I prove it wrong? Of course I can. When we align with something fully and it doesn't come, LoA is falsified. Hasn't happen to me yet.
2) Can we repeat it and get the same results? Yes, many people do that with relationships for example.
3) Does it allow to make predictions? It's always easier to look at other people and make predictions for them, but yes, it's easy to read vibration. You just need to listen to what people are telling you or to be aware of your own thoughts.

You see, the theory behind LoA has a lot of potential, even when you look at it in a scientific way.

Now, let's put all the pieces of the puzzle together:
Why do we script? To experience the thoughts and feelings of our manifested desire.
Why do we visualise? For the same reason.
Why do we act as if? For the same reason.
Why do we mediate? To slow down our thought process and prevent us from thinking thoughts that draw to us the things we don't want.
Why are we supposed to reach for the best avaible feeling? Because feeling good means that we are aligned with what we want.

It all fits together perfectly.

But there is still one part missing. Are there any premises we need to assume, so that this theory can work? And yes, there is one. You create your reality. I create my reality. I want this specific car/person/fir cone and focus purely on having it. You want this specific car/person/fir cone and focus purely on having it, too. Who gets it? If the theory is correct, the answer should be: both of them, there is no other way. Else we wouldn't create our own reality, but create random parts of our reality and that would be a very bad and useless theory without the ability to explain or predict things. So the theory that we create our complete reality is obviously better, but we need a new model of the world to make it possible. We need a world with an endless number of that specific car/person/fir cone, we need parallel realities.

And suddenly, we have a model that explains everyting, that makes it possible to make precise predictions and most important is practical. I will end with he words of Kurt Lewin: "There is nothing more practical than a good theory". So let's put it into practice