Fully defensive riding, as above (changing road placement as cars pass/approach, covering brakes* as you see upcoming junction, watch the wheels at roundbouts if they’re not indicating, eye contact, always stay outside of dooring range etc etc).
Set your commuter up for surviveability- Topeak folding mirrors, epic brakes, grippy tyres and learn how to stoppie so you can brake at 100% in an emergency.
There’s only so much you can do, yes, but it’s also a lot more than nothing.
(I also don’t tailgate cars into clear roundabouts at 40kph anymore, they might stop for no discernible reason and I have had enough experience of smashing the rear window with my face. I don’t dart across gaps in traffic, you may fall over on diesel and land in the path of an oncoming bus. – these last two are my own stupidity, but worth noting perhaps)
*this also requires correct body position – don’t be standing up and stomping on the pedals when there’s a chance you have to do an emergency stop – you need to be seated and ready to transfer the weight hard backwards if you have to emergency stop.