"A nice review in the Sunday Times by X"
One of the things I do is help authors with a book. Typically, these are authors who have a contract to publish in several countries, and want support and ideas as they write the manuscript.
The work might take a whole year, perhaps more. Mostly we do it over Zoom.

Portrait from memory of Author W. N. in his office.
Typically, we discuss each chapter before it’s written, then when it’s done I read and comment and suggest edits. I make marks on paper, with a red pen, then scan them and send back via email.
Then we discuss the next chapter.
The last thing we do is read the whole book as a whole book and compare it with the book proposal to ensure that the author has not only done what was promised but surpassed that.
One author I worked with sent me this message in the week his book was published: