No single SEO factor will guarantee search engine rankings. Having a great HTML title won’t help if a page has low quality content. Having many links won’t help if they are all low in quality. Having several positive factors can increase the odds of success while the presence of negative factors can worsen those odds.SEO is all about optimizing a website for search engines. SEO is a technique for designing and developing website to get rank well in search engine results. Improving the volume and quality of traffic to a website from search engines. Internet marketing by understanding how search algorithms work, and what human visitors might search.Search engine optimization is often about making small modifications to parts of your website. When viewed individually, these changes might seem like incremental improvements, but when combined with other optimizations, they could have a noticeable impact on your site's user experience and performance in organic search results.The number and quality of backlinks remain extremely important for the ranking.The number and quality of backlinks remain extremely important for the ranking. Social signals continue to become stronger as a factor for ranking. Quality and relevant content remains a key factor.
If you are talking about the numbering then it can be like following:-
1. Internal Links
2. Social Links (FB and Twitter)
3. Unique content
4. Keywords in title
5. Keywords in content
6. External linking
7. Keywords in url
8. Freshness of pages
9. Keyword in H1 tags
10 Keywords in image tags
I've responded to the question as you asked but really these factors all play a role, small and large. The key to great rankings is to try and get all of these factors (and a few more) in place. SEO is a science where a lot of small factors add up to a large benefit.
Here I discussed certain site wide factors that can improve sites ranking.
•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 Backlinks 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 server’s location helps to boost rankings for that specific country or region.
•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 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 optimize your site.