Be intimately familiar with, and fully accepting of and comfortable with, every culture that applicants may potentially come from.

Or, explicitly require / assume that all applicants be fully familiar with your culture.

Or, define an industry standard artificial culture - whether implicit or explicit - and require everyone on both sides to be familiar with it. This could include things like suits and golf for execs, hoodies and beer for techies, social justice activism for webdevs, etc...

I'm hardly an expert, though I'd probably suggest focusing on avoiding the four pitfalls I mentioned. Like any hard process, it involves working hard to achieve gradual improvement, learning from others where appropriate.

However, I can guarantee that resting on your laurels and calling your process "unbiased" from the start won't work.