Google Ranking Factor

On-Page factors:

The way your page is optimised has the most profound effect on its rankings. Here are the page optimization factors that can affect its search visibility:

Keyword in 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 pages content. 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.
Ideally, the keyword should be placed at the start of the title tag. Pages optimized this way will rank better than those with keyword closer to the title’s tag end.

Keyword in description tag.

The importance of the meta description tag today is often discussed in SEO circles. It is nonetheless still a relevancy signal. It is also crucial for gaining user clicks from search results pages. Including keyword in it makes it more relevant to a search engine and a searcher.
Keyword in H1 tag. H1 tag is yet another relevance factor, serving as a description of the pages content. In spite of an ongoing discussion about its importance, it is still a good practice to include your keyword in a unique H1 tag on a page.

Using keywords in the pages copy.

 Up until not long ago, stuffing your page with keywords was a surefire way to increase its rankings for a particular keyword. That’s not the case anymore. Using the keyword in the copy still sends a relevancy signal of what the content is about. How you place it however has changed drastically.

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. And it’s a common sense that the longer your content is, the greater the chance that you can cover more aspects of your topic. Don’t be shy of writing long but highly useful copy then.

Duplicate content.

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. Avoid duplicating content and write original copy for each page.
Canonical tag. Sometimes however having two URLs with similar content is unavoidable. One of the ways from preventing this from becoming a duplicate content issue is by using a canonical tag on your site. This tag does one simple thing, it tells Google that one URL is equivalent of another, clearly stating that in spite of two pages having the same content, they are in fact one.

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 instance.
Content Updates. Google algorithm prefers freshly updated content. It does not mean that you have to edit your pages all the time. I believe that for commercial pages, such as product descriptions Google recognizes the fact that they are not as time sensitive as blog posts covering recent events. It is wise however to include some strategy to update certain types of content once every 12 months or so.
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. This can be a huge trust factor for Google. Too many outbound links however can greatly diminish the page’s PageRank, hurting its search visibility. Outbound links can affect your rankings but use them in moderation.

Internal links.

Interlinking pages on your site can pass their strength between them.
Keyword in URL. Including keyword in the URL slug (that’s the bit that appears after the “.com/“part of the URL) is said to send another relevancy signal to Google.
Site factors:
There are certain site wide factors that can affect your sites search visibility as well:

Sitemap.

 A sitemap helps search engine to index all pages on your site. It is the simplest and most effective way to tell Google what pages your website includes.
Domain trust. Trust matters. It’s hard no to think that sites Google trusts should rank higher. But how do you build that trust? Brian from Backlinko has a full list of trust factors here. Needless to say, building trust factors of your domain will certainly pay off.
Server location. Some SEOs believe that a servers location helps to boost rankings for that specific country or region.

Mobile optimised 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 optimised site would affected rankings in some way.
Google Webmasters Tools integration. Lastly, having your site verified at Google Webmasters Tools is said to help with your sites indexing. Even if that’s not the case, the tool provides valuable data you can use to better optimise your site.
Off Page factors:
When ranking your pages, Google looks at factors outside of your site as well. Here are some of the key ones:

The number of linking domains. The number of domains linking to you is one of the most important ranking factors.
The number of linking pages. There might be a number of links from a particular domain to your site, their number is a ranking factor too. However, it is still better to have more links from individual domains rather than from a single domain.

PageRank of linking page

. Not all pages are equal. Links on pages with higher PageRank will be a bigger factor than those on low PR pages. Therefore, you should strive to build links from high PR pages.
Link relevancy. Some SEOs believe that links from pages related to your pages topic carry more relevancy for search engines.

Authority of linking domain

. Similarly to a page PR, the authority of a domain may be a ranking factor too. For that reason, a link from low PR page on a high PR site will be worth more that from a lower PR one.
Links from homepage. Similarly, some SEOs believe that links from a home page of a linking domain carry more strength than those on one of its pages.
Number of dofollow vs. nofollow links. Google officially stated that they don’t count nofollow links (link with rel=nofollow attribute attached). Therefore the number of your do follow links should affect your rankings too.

Diversity of link types.

The types of links you build to your site matters too. Too many links of one type may be a spam indicator and impact your rankings negatively.
Contextual links. It is said that links within the content of the page are worth more than links in a sidebar for instance.

Link anchor.

 Anchor text of a link used to be a strong ranking factor. Today it can be used as a web spam indicator, negatively impacting your rankings.

Domain factors:
Lastly, your domain can affect your rankings as well. Some of the domain signals aren’t as strong as they used to be, there are few things worth paying attention to:

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 penalised in the past, its history might affect its current rankings
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Country TLD extension. If you try to target a specific local market, it is said that having a domain with a country specific TLD (.pl, .co.uk or .ie for insance) will help to achieve better rankings for that location.