I have a book by a Royal Academician who does not once mention "focal point" throughout, tho there is a discussion about the golden mean.
He does say this, which I have always found helpful:
"The painter who doesn't know anything about composition is still, inevitably, composing when he sits down to paint even the simplest subject. he cannot put down one shape or line onto an empty canvas without creating a composition of sorts. But his very limited sense of placing and design is likely to be dominated by stereotyped ideas, of the sort of negative instructions people remember vaguely from schooldays - don't put the main subject in the middle
and other "rules" of that sort. What we can try to do is to think about the business of composition - not in order to find out how to do it, but simply to become more aware of the possibilities, so that the way is opened for greater variety in our approach to picture-making.......it is only on the basis of knowledfge that we can become free to compose naturally".
I like the idea of being free to compose naturally.
I also adore this image, which breaks all the rules: (Paul Millichip, deceased, award-winning British painter)