I remember reading a book by David K. Reynolds about Asian Psychotherapies where he said in the U.S. we come up with theories about why therapies work, but in Morita and Naikon therapy, they just concern themselves with what works, and they don't bother trying to explain it. One of their treatments is solitude, for example. They don't allow the patient to do anything but sit in a room. After awhile, the person wants something to do, so they allow the patient to do some sweeping and cleaning. The therapists have no theory to explain why this cures people. They just know it does, so they use it.
Reynolds called it a sort of phenomenological operationalism. I guess that's a good name for my philosophy. I think of these ideas as tools and my book as a toolbox. With any given task, some tools will be better than others. The question is, what's the best tool for the job? Some tools are effective for many different tasks. For example, exercise. It's a good tool for a lot of tasks: trying to lose weight or be happier or sleep better or get along with people better or pull out of depression or reduce anxiety. And some have a more specific application. Those tools are only good for one thing, even though they may do that one thing very well.
In the book, Think and Grow Rich by Napoleon Hill, he describes 13 principles. One of them is autosuggestion. The principles are excellent, but his explanation of them, his answer to why it works, seems silly. He talks about sending "thought vibrations" into the "ether." That was a popular theory of his day. But you don't need the theory, and in some ways, for regular people (rather than researchers) you'd even be better off without the theory, since probably it will change, even though the principle may remain as true as ever.
So this is one view of my personal philosophy: I like theories and I even entertain some, but the important thing, and the thing I try to keep to, is what works.
Read about the basic principles behind Self-Help Stuff That Works and Principles For Personal Growth.