Ask HN: How do you optimize your microbiome?

While there are a lot of resources about how important the microbiome is to our physical and mental health, there seems to be little solid advice for how to optimize one's microbiome.

My impression so far appears to be to: * avoid anti-biotics * avoid probiotics (unless prescribed by our doctor after a recent course of anti-biotics) * go for fermented foods like Sauerkraut, Kimchi, Kefir, ... * increase your intake of fibre rich foods, * ?

What else?