[jetcata]

It's fairly simple - zero tolerance when it comes to harassment is a great place to start, offenders are sent packing.

Leadership sets an example of what behavior is acceptable and what isn't and management enforces it.

You also look out for culture fit when hiring - you don't just hire on technical competency, you also actively check that someone isn't an asshole, no matter how well they perform.

Edit: The question is, what will you do with the above advice? Will you take action and make improvements? Because otherwise this discussion was for nothing.