The Art of the Impersonal Essay

Zadie Smith, on essay writing for The New Yorker, making it sound easy (paywalled once more, I apologise). In-between the lines, her most puzzling admission, for me:
(I still write the opening and last lines of an essay first.)
Fascinating. The meandering form of an essay is difficult enough to master, let alone knowing where you'll end it before you commence.
“Bob's your uncle".