All SEO claims should come with a warranty
There is a lot of contradictory advice on SEO. For example something as simple as whether http or https is better is up for debate. Google has themselves announced that they will reward sites for using HTTPS/SSL. Due to Google’s dominance in the search engine space it may be safe to assume that HTTPS will improve your rank. However a conflicting ranking variable is site loading speed. HTTPS can prevent intermediate caching and requires a more lengthy handshake to complete a transaction. This is the reason that Google developed the SPDY protocol. So now we have three options to which it is not clear what mix of speed and safety will achieve the greatest respect in Google’s algorithm. That is just one search engine, other portals or engines may analyze your site very differently. Personally I have not found any statistically significant difference between HTTP or HTTPS with regards to search engine ranking.
For more practical advice it is always best to consider what produces the best customer experience. It should be assumed that this is the goal of both the portal and site. So let’s breakdown a few features that improve site usability: speed, portal navigation, site navigation, content quality, and traffic quality.
Speed is easy enough to measure. Google provides tools to analyze your site speed and find ways to improve. Good advice is simply engineering your site well and using a CDN.
Portal navigation depends on what context your site will be appearing. The two most common contexts would be Google and Facebook. For both it is good advice to have a readable title and page meta description. For Facebook a good image is also helpful. Mobile consideration is also important, and again Google has a tool to help with that.
Site navigation is up to your designer. For crawler accessibility it is also important to make all your public links such that the spider won’t wrap itself into a loop. Also unique pages should not be hidden behind URL parameters.
Content Quality is probably the most important of all considerations, but also has no singular solution. Track your users and make sure that your site is engaging and users are staying on the site for longer and returning. Search engines have lots of information regarding entry/exit, so good traffic patterns are rewarded.
Traffic Quality is simple enough. Don’t spam and you won’t get spammed. Don’t buy traffic and avoid fraudulent clicks. Moz has a tool to help see how reliable your upstream links are.
I purposely left out Page Rank, because it has been reported as less and less of a rank predictor. Google is moving to new algorithms that look more at consumer experience and less at in-bred linking schemes.
That is all I can think of for now. If anyone has tips feel free to leave them in the comments below.