Every SEO tool produces a list. Two hundred findings, grouped by category, each with a colored dot. The list is rarely wrong. It is just in an order that has nothing to do with impact.
The reason is mundane. Tools sort by what they can count reliably. Three hundred missing alt attributes produce three hundred rows and therefore look urgent. One forgotten noindex produces one row. For rankings, the first is close to meaningless and the second is fatal.
The real work in an audit is not finding things. It is ordering them.
Level 1: can the page be seen at all?
Nothing below matters while something here is broken. Four failure patterns cover most of the cases.
The noindex left over from staging. Still the most common serious fault after a relaunch. The staging environment sets a robots meta tag so it stays out of the index. Somebody forgets to remove it when the site goes live. Three weeks later a person notices traffic is down eighty percent.
The canonical pointing at the home page. Misconfigured plugins sometimes put rel=canonical on every subpage pointing at the root URL. Google reads that as a statement: all of these pages are copies of the home page. And treats them accordingly.
Blocked resources in robots.txt. A Disallow on the folder holding CSS and JavaScript does not prevent indexing, but it does prevent Google from rendering the page the way a visitor sees it. What it gets instead looks like an unstructured wall of text.
The empty shell. The page assembles all its content in the browser and the server returns a skeleton with no words in it. That often works. It does not always work, and it does not work everywhere.
The tool for this level is not a crawler. It is the page indexing report in Google Search Console, which states in writing which URLs were excluded and on what grounds. Skipping that report and crawling instead means looking for the answer inside your own site while Google has already written it down for you. If you have not set up Search Console yet, the route to it is in setting up Search Console.
Level 2: does the page answer the question it should rank for?
The most underrated point in the entire discipline. A page can be technically flawless and still show up nowhere, because it answers a different question from the one being asked.
A roofing company wanted to rank for "roof replacement cost". The page held the company history, a paragraph about craftsmanship, the phrase roof replacement four times and not a single number. Ahead of it sat three pages with square meter prices and a worked example. That is not a technical problem and it is not a word count problem. It is an intent problem.
The check takes five minutes per page. Take the top query from Search Console, read the page with that question in mind, and time how long it takes to reach the answer. More than fifteen seconds and you have found the issue. Matching queries to pages is covered in analyzing user behavior.
Level 3: technical faults a human notices
Only now does it get technical, and only for things a person can actually feel.
Load time on a phone comes first. Not for the score, but because a visitor waiting four seconds for the first visible element is frequently gone before it appears. The single most common cause is still an oversized image near the top of the page. A 2.4 megabyte background image is not a rare sight.
After that: shifting layouts, dead internal links, and tap targets sitting too close together on a phone. These things rarely produce a ranking jump. They decide the margin, whether a shaky fifth place turns into a third. How to measure and fix load time and shifting layouts specifically is in improving Core Web Vitals.
Level 4: everything you do once the rest is fixed
Alt attributes, structured data, tidy sitemaps, readable file names. This is maintenance, not repair. Starting here because the list has three hundred entries means spending an afternoon and changing nothing.
Half the list is not a problem at all
Something no tool volunteers: a good part of what it marks red is not a problem on your site. Tools have to warn in general terms, because they do not know your context. So they flag "meta description missing" on a page where Google pulls the description from the text anyway, and "title too short" on a page whose short title is exactly right.
The most common false alarms you can safely leave standing: duplicate meta descriptions on pages barely anyone finds through search; a missing H1 on a pure redirect page; "thin content" on a contact page that has exactly one job. The skill is not working through every line, it is recognizing which line matters on your page at all. A tool that returns two hundred findings is not thorough. It is just unspecific.
The sorting rule
When two findings compete and you cannot decide which one goes first:
Pages affected, multiplied by the demand those pages have, divided by the effort to fix it.
A noindex on a page pulling four hundred clicks a month beats three hundred missing alt attributes on pages nobody visits. A fault on a page with no demand at all is not a fault, it is a note for later.
One caveat that matters: measure demand by impressions in Search Console, not by your own expectations. Pages everybody in the company is certain are important turn up with three-digit impression counts surprisingly often, while a forgotten subpage quietly runs in the tens of thousands.
What to open first
Search Console, page indexing report, the "not indexed" section. Work through the three most common reasons there before touching any other tool. Then take the pages with the highest impressions and the worst average position, because that is where the largest gain in visitors sits. Why that particular range is the cheap one is explained in increasing website traffic.