I have a thing for openings. And endings. Well, and transitions from time to time, and...
Before I began writing fiction, seriously writing, I paid little attention to technique as I read. Every book I read, I read for pleasure.
Several years ago while on vacation, I took a paperback book that I love immensely, 13 Little Blue Envelopes by Maureen Johnson, and marked the hell out of it with a highlighter. I underlined transitions between scenes, favorite end-of-chapter paragraphs, and how she described settings. Then I went through it again and noted how she introduced her characters, handled emotional conflict, and built suspense. There were other details I looked for, but I zeroed in on those examples in that particular book. It was a tedious exercise, but pretty enlightening.
When I love a particular book, there are certain broad elements that always stand out to me. In the books I've read most recently, it was voice in The One and Only Ivan and Our Own May Amelia; the vivid settings in The Forest of Hands and Teeth and Divergent; and I loved the characterization and dialogue in The Fault in Our Stars and Wonder.
Each of those books would be at the mercy of my highlighter if I had the time to study each author's skill at writing those books. Too many other books to read and stories of my own to write keep me from repeating the 13 Little Blue Envelopes exercise, but I encourage you to try it. Being a writer means there's no end to learning how to be a better one, and what better teacher is there than a well-written book.