Ergh, OKish except I quite strongly disagree with the first tip. If you have so many closing divs at the end of a document that it's hard to tell which close-div closes which open-div then you were doing it wrong at the outset.
Commenting the close-divs is a dirty workaround to a bad code smell. Sort out your markup and prune out the superfluous junk. You'll find that the "sea of close divs" problem solves itself without need for comments like this.