The SEO audit is for the most part the on-site factors of your website SEO. By having an audit and addressing any issues, it helps the search engine read and interpret your content correctly. Having the search engine correctly understand what you are trying to convey to people helps you get read by your target audience.
Keyword use used to be important for on-site SEO, but, not so much anymore. It’s relevance that’s important. How relevant is your article in the search results by the person making the query? By making your article relevant, you are trying to create a page that satisfies the query of the user as opposed to creating “spam” pages that just tries to get to the top of the search engine for the sake of it.
In summary, the SEO audit will help you create an article that gets read by the search engine properly. Subsequently, your content will be read and hopefully satisfy the people who are searching for articles that matches your content.
An SEO audit can include checking and / or analyzing:
HTML validation
This checks that the code behind your web page is correctly written. It’s basically a “grammar and spelling” check of the coding.
Bad links
Does your site have links with the incorrect url? Fixing bad links improves user experience by not having them land on a 404 Not Found error page.
Redirects
Are old links redirected to new ones? If not, they can be redirected so that users do not end up with a 404 Not Found page. This improves the user experience.
robots.txt file
Do you have a robots.txt file. And if so, is it correctly written. This file helps search engines crawl your site by excluding directories and files that should not be looked at.
404 Not Found page
Do you have a Not Found page that helps users when a link is broken or not found? Having a good 404 page can mitigate bad user experience when broken links are found on your site.
Indexing issues
Are all the pages you want to be found in the search engine actually in the search engine?
Crawling issues
Are there any issues when the search engine reads your website?
Page load time
How fast does your web page load in the browser? The faster the better.
Site maps
Are you using a site map which is a table of contents for your website? Site maps helps search engines crawl your site.
Linking
Are you linking correctly within your website? Good links help user experience and keeping them current helps prevent not found errors.
Page titles
Are you using relevant page titles? Good page titles can attract users and improve SEO. They are a very important factor in SEO.
Meta tags
Do you have descriptive meta tags? Good descriptions can attract readers.
Duplicate content
Do you have duplicate content issues in your website? Duplicate content issues can reduce your ranking.
Images
Are you images labelled? At least 1 labelled image can help the SEO of your page. The label includes the alt tage and the file name of the image.
Content
Is your content relevant?
Navigation
Is it easy for user to find your content? Does it make sense?
If you notice, user experience appears very important in SEO. And that’s because search engines want to send good, easy to read information to users. There are more factors, but, these are the ones I consider the most important, although, not in that order.