Do you work on a big company site where everything is within the secure protocol? If so, these are what you have to  keep in mind for your onsite optimization:

1. If done right, an https site can rank as well as an http site.
2. Keep all your certificates valid, all the time, 24/7/365.
3. Https sites are more work for the servers, so there is the possibility of a slower download. Keep your site and the certificate on a high performance host. If it takes too long to download a site Googlebot might go bye bye.
4. The https-site and the http-site are two completely different sites; it’s a little bit like having a www version of the site and a non-www version. Make sure you have 301 redirects from the http URLs to the https ones.
5. The robots.txt is only valid if placed within the same protocol as the site. Place it within the https protocol. 
6. The same goes for the sitemap.xml, Google verification file, and the other stuff.

Additionally: Keep all your files (images, iframes, etc) within the https protocol. There still is a nasty pop-up in Internet Explorer (6, maybe 7 too) if done otherwise. 

Maybe there is a fall off in click- through due to the display of the https:// part in front of the www (which does not happen for http:// sites). Does anybody has information about this?

thx for your screentime,
FranzSEO