Editing, like sending thank-you cards, is one of those things that
everyone acknowledges is a good idea but few people do. It takes time
and you don’t reap much reward, certainly not equivalent to the time.
There is probably not enough attention to teaching writing in graduate
school, but at least you have plenty of models and plenty of chances to
practice.

Models of editing are scarce — that is, unless you work with
commercial presses or magazines. There, editors really edit. We think
of those venues as shallow slaves to the market, but they often pay
more attention to the words and ideas than we do. They never lose sight
of their audience, holding the quaint assumption that writing is
actually written for people — not for tenure or a CV, both of whom are
tone-deaf. — Jeffrey J. Williams, Chronicle