You must first go over all of the current content on the site. You can use MozBar for that.
Local Search audit – open Google My Business. GMB is where you can manage things like reviews, contact information, locations, opening hours, photographs, posts, and now direct messaging for local search optimization.
On-page SEO audit – check all aspects of a website’s structural SEO, such as word count, sitemap presence, robots.txt, meta description, titles tags, heading tags, image alt tags, and Schema.org structured data. Useful free tools you can use: Keyword Density & Consistency Tool , Website Word Count Tool , XML Sitemap Checker , Robots.txt Checker
Website load speed – If the page script load time exceeds 10 seconds, you’ll need to list each plugin and their load time breakdowns to figure out who’s to blame. If a plugin is inactive or has little value, it should be removed.
Broken links – List all of the broken links in a spreadsheet so that the client can map them to new destinations or delete them entirely. This free Broken Link Checker scans pages for broken links and allows you to quickly fix them.
Social Media audit
Organic and paid social audit: Use a social media analytics tool like Sproutsocial to evaluate the organic and paid performance of content on major social media channels like Facebook, Instagram, Twitter, YouTube, and LinkedIn. Check organic social metrics such as: Impressions, Engagement Rate, Total Interactions, Monthly Growth Rate, Clicks, Conversions.
Competitor analysis : Make sure you compare the client to all relevant competitors to see what the current “average” performance is.
Ensure that the Facebook Pixel, Facebook Open Graph Tags, and Twitter Cards are all in place on the client’s website before moving on to paid social.
Earned social audit: Use a social media listening tool like Hootsuite to discover conversations and mentions by keyword for earned performance (public mentions on social media from word of mouth). You should answer these three key questions when performing social listening: Where are the conversations taking place?, What are the topics of discussion?, Who are the people who are driving the discussion?