I'm sure I learned a lot about writing from each of the writers I devoured, but I'd have a hard time putting my finger on telling you exactly what.
Anyway, I realized I could make something like a timeline of my obsession authors at different ages. This list isn't exhaustive, of course. For fifteen years I regularly read the annual Year's Best SF collection cover-to-cover every year, and sampled a lot of writers on the way. Also this list doesn't include poets, historians, biographers, science writers, etc. The dates are approximate, and don't reflect the actual first or last time I read a particular writer, just the period of my greatest concentration on that person. Nor does it include ongoing, long-term writers whose works I return to over and over, like Shakespeare, Tolkien, etc. I also had comparatively brief periods where I read a very small number of works by particular writers (Robert Sheckley and Alfred Bester come to mind) which didn't stretch out into long-term habits like these. And of course there are a lot of authors of whom I've read only one book, but it's a book I adore.
But for what it's worth:
These days I read rather differently, both because I read many more short stories than novels and because I make a concerted effort to sample widely within the genre.