The sequence: verify conversion tracking end to end, check the change history for the last 90 days, read the search terms report before the keyword list, audit the negatives, then look at structure. Structure is last because it is the thing everyone wants to rebuild and the thing that matters least if tracking is broken.
Four findings appear in almost every audit. Conversions counting something that is not a conversion. Broad match with no negative discipline. Budget concentrated in one campaign nobody has questioned in a year. And a landing page that contradicts the ad.
The deliverable is written, with a priority order and an explicit list of what we are deliberately not changing yet. That last section is the one partners find most useful, because it is the answer to a client asking why everything did not change in week one.