1. the volume of incoming links from similar websites
2. quantity and quality of content
3. technical precision of source code
4. spelling,
5. functional v. broken hyperlinks
6. volume and consistency of searches and/or viewer traffic
7. time within website
8. page views
9. revisits
10. click-throughs
11. technical user-features
12. uniqueness
13. redundancy
14. relevance
15. advertising revenue yield
16. freshness
17. geography
18. language and other intrinsic characteristics.

Keep these 18 factors in mind when launching a new SEO campaign for 2013. Content is king, keep your page fresh, relevant and easy to navigate/read and your already ahead of your competition.