HTTPS is just another signal that is being added to more than 200 others.
While security is very important, HTTPS is far of greater importance for sites that are processing orders or acquiring user data when visiting.
Google will be releasing the best practices soon enough, but in the meantime here are some basic tips to get started, as they recommend:
- Decide the kind of certificate you need: single, multi-domain, or wildcard certificate
- Use 2048-bit key certificates
- Use relative URLs for resources that reside on the same secure domain
- Use protocol relative URLs for all other domains
- Check out our Site move article for more guidelines on how to change your website’s address
- Don’t block your HTTPS site from crawling using robots.txt
- Allow indexing of your pages by search engines where possible. Avoid the noindex robots meta tag.
Link: HTTPS for SEO