First Page Sage is the largest pure SEO company out there. Each year, they do a study of the top ranking factors in Google Search based on a large number of clients and what brings success or failure to their SEO campaigns on Google.
I have not published the entire list, but have listed the top 10 factors and the percentage of success that is attributed to them from the study below:
Consistent Publication of High-Quality Content 25%
Note: Content must be high quality “thought leadership” content posted at least twice per week. Thought Leadership Content focuses on using the expertise and experience of the people behind your brand to address or answer any questions or concerns your audience or customer base might have.
Keywords in Meta Title Tags 21%
You must include the keywords you wish to rank for in your title tags, you have very little chance of ranking
Inbound links still weigh heavily in Google’s trust of a website, they should be less of a concern than publishing great content regularly
Internal Links from Related Articles 8%
The more pages your site contains that target a long-tail version of a keyword and link to the main page targeting that keyword, the more authoritative Google considers the main page.
Mobile-Friendly / Mobile-First Website 7%
Google has created a mobile first indexing world. Performance, content and information on your mobile site is key to gaining SEO placement on Google.
Visitor Time on Site 7%
Visitor time on site is an excellent indicator of the quality and value of your content. Google has adopted this metric as a ranking factor.
Site Speed 4%
Load speed of a site has always been a key factor in user experience. User experience is part of the quality of content/time on site equation.
Site Security / SSL Certificate 4%
Google does not want to be a part of featuring websites in search results that are potentially harmful to site visitors. If your site lacks an SSL certificate (indicated by the “s” at the end of “https”)—it will lose ranking ability. Secure certs are now the norm and are easily installed in most cases, by your site host.
Offsite Mentions 3%
Mentioning a site is the same as a link, without the hyperlink. Therefore, it has become a ranking factor.
Schema Markup / Structured Data 2%
Google prioritizes pages in search results that use schema markup because it makes search results more useful to users. They also cause search results to stand out from the rest of the others on the page which can help to boost conversion.
Google continues to strive to fulfill its mission of creating the best possible search experience for its users by serving those users fast, relevant, and high quality search results. These 10 factors, especially the top 3-High Quality Content, Keywords in Meta Title Tags and high quality relevant Backlinks that a human would actually use, are the biggest factors in creating successful SEO campaigns.