Written in 1983 and still the most useful book on advertising I have read, which is slightly depressing for the forty years since.
The method is research first, long copy if the product warrants it, and a headline that says something rather than being clever. He is openly contemptuous of work that wins awards and sells nothing.
The specifics about print layout are obsolete. The discipline underneath, that you are selling a thing rather than expressing yourself, transfers directly to digital and is ignored just as often.
Read December 2015, while running a digital agency team.