How to track changes in a layout document
Type > Track changes in Layout by Zaweba marks added and deleted text by author and time, so edits can be reviewed, accepted or rejected story by story.

Choose Type > Track changes in Layout by Zaweba and every edit in that story is recorded with the author's name and the time. Typed or pasted text is marked as added, deleted text is kept and marked rather than removed, and paragraph breaks and moves are recorded too. A Track changes panel lets you step to the next or previous change and accept or reject one, all of them, or every change by a single author.
This brings the familiar word processor habit into the layout. Late corrections often arrive after the text is already on the page, and tracking them in place means the editor can see exactly what changed without comparing printouts.
How tracking works
Tracking is turned on per story, so you can follow changes in a feature article while leaving the furniture of the page alone. Each change is shown in its author's colour on the page, which makes it easy to see who did what when several people touch the same text. The marks are for review only. They are never printed and never exported, so you can't accidentally send a PDF full of red deletions to the printer.
A sensible review routine
Agree with the team that tracking is on for any story past first proof. From then on, every edit, whether a comma or a rewritten paragraph, is visible. The person responsible for the text then goes through with the panel, stepping from change to change.
Accept the changes that are right and reject the ones that aren't. If one contributor's edits are all approved, accepting all changes by that author clears them in one step. When the story is clean, tracking can stay on for the next round or be turned off once the text is signed off.
It helps to read changes in context rather than one by one in isolation. A cut that looks harmless on its own can leave a sentence that no longer makes sense, and seeing the whole paragraph on the page shows that at once.
Where it fits with the other editing tools
Track changes is one of several tools for working on text that has already been laid out. The story editor gives a plain-text view of a story with its paragraph style names, which is often easier to read when checking a long piece. Notes let editors leave comments in the text or on the page without changing the words, and comments from a Word document can arrive as notes when it is imported. Find and change, including GREP searches, handles corrections that repeat across a document, and the spell check uses a UK English word list with your own dictionary.
Used together, these let a small team run a proper editorial process without leaving the layout program. Writers and editors agree text in Word if they like, it is imported, and late changes are made and reviewed in place.
Easy things to overlook
Remember that tracking is per story. If you are reviewing a whole magazine, check that it was on for every story you expect, not just the first one someone opened.
Moves are recorded, but a large rewrite can still be hard to follow if it is done as a delete and retype. Encourage contributors to make small, targeted edits where they can.
Accept or reject everything before final output. Although the marks don't print, a story full of unresolved changes is a sign that the review isn't finished, and it is easy to miss that a deleted sentence is still in the text because nobody rejected the deletion.
Finally, save a copy of the document before accepting all changes on a big job. It costs nothing and gives you a record of what the text looked like before the final round.