What must we do to be Hummingbird-friendly?

Let me ask you few questions, and try to answer them sincerely:
  1. When creating/optimizing a site, are you doing it with a clear audience in your mind?
  2. When performing on-page optimization for your site, are you following at least these SEO best practices?
    1. Using a clear and not overly complex information architecture;
    2. Avoiding canonicalization issues;
    3. Avoiding thin-content issues;
    4. Creating a semantic content model;
    5. Topically optimizing the content of the site on a page-by-page basis, using natural and semantically rich language and with a landing page-centric strategy in mind;
    6. Creating useful content using several formats, that you yourself would like to share with your friends and link to;
    7. Implementing Schema.org, Open Graph and semantic mark-ups.
  3. Are your link-building objectives:
    1. Better brand visibility?
    2. Gaining referral traffic?
    3. Enhancing the sense of thought leadership of your brand?
    4. Topically related sites and/or topically related sections of a more generalist site (i.e.: News site)?
  4. As an SEO, is social media offering these advantages?
    1. Wider brand visibility;
    2. Social echo;
    3. Increased mentions/links in the form of derivatives, co-occurrences, and co-citation in others' web sites;
    4. Organic traffic and brand ambassadors' growth.
If you answered yes to all these questions, you don't have to do anything but keep up the good work, refine it, and be creative and engaging. You were likely already seeing your site ranking well and gaining traffic thanks to the more holistic vision of SEO you have.
If you answered no to few of them, then you have just to correct the things you're doing wrong and follow the so-called SEO best practices
If you sincerely answered no to many of them, then you were having problems even before Hummingbird was unleashed, and things won't get better with it if you don't radically change your mindset.
Hummingbird is not asking us to rethink SEO or to reinvent the wheel. It is simply asking us to not do crappy SEO... but that is something we should know already, shouldn't we?