Domain registration length. Google considers domains registered for longer than a year as more trustworthy. QUOTE.
Domain history. You may not be the first person who registered the domain. And if your domain has been penalized in the past, its history might affect its current rankings. If you try to target a particular local market, it is said that having a domain with a country-specific TLD will help to achieve better rankings for that location.
Keyword in the title tag. The title meta tag is one of the strongest relevancy signals for a search engine. The tag itself is meant to give the accurate description of the content of the page. Search engines use it to display the main title of a search result. Including a keyword in it will indicate to search engine what to rank the page for.
The length of the content. These days searchers want to be educated and won’t satisfy with basic information. Google, therefore, looks for authoritative and informative content to rank first.
Not all factors can influence your rankings in a positive way. Having similar content across various pages of your site can actually hurt your rankings.
Image Optimization. It’s not only text that can be optimized on a page but other media too. Images, for instance, can send the search engine relevancy signals through their alt text, caption, and description for example.
Internal links. Interlinking pages on your site can pass their strength between them.
Outbound links. Linking to authoritative pages sends trust signals to the search engine. Think of it this way, the only reason why you would send a user to another site is if you wanted them to learn more of the subject.
Mobile optimized site. Only a year ago, 46% of searchers used mobile exclusively to research. I believe this number increased exponentially in the last 12 months. It would be no surprise then that having a mobile-optimized site would affect rankings in some way.
Lastly, having your site verified at Google Webmasters Tools is said to help with the indexing of your site. Even if that’s not the case, the tool provides valuable data you can use to optimize your site better.