haven't read yet but you can start by not calling anyone who disagrees with the established view a contrarian. It implies anyone who disagrees is doing so to play out a role rather than out of actual disagreement.

edit: so it seems that people who are playing out a role is exactly what you want more of. I assumed you were using "how can we get more contrarians" as codespeak for how can we get more disagreement. If you just want more actual "contrarians", well, I'm not sure "contrarians" is a real category. In any case it's not the relevant category. What you want is people who like criticising things, not people who like disagreeing with established opinion (again I really have to emphasise how ridiculous the way "contrarian" is used is. It's blatantly a story someone has made up to ad hominem away criticisms of standard ideas.)

For my part I would not feel comfortable finding fault in everything I see here. I know I can do it, I just don't think it would go down well. Not that it tends to go down well many other places either. part of the problem is something like people being too comfortable talking in terms of e.g. evolution's intentions so good criticisms can be dismissed as pedantry.

I might make a contrarian account though and see how well that goes down.