None..they are really still heavy on backlinks..and this should be your only focus to grow your site.
I have to second poppaippi, in that backlinks are definitely still an area Google is focusing heavily on. As always, quality backlinks are the most optimal in improving your SERPs and acquiring links from a wide variety of unique domains will have the biggest impact.
For being updated always read google's own blog googlewebmastercentral.blogspot.com, it is very fine and helps much keeping you informed