The most important rule in life is “don’t be an idiot”. This applies to all.

Drivers: pay attention. Follow the rules of the road, unless doing so in a specific situation is less safe than not following them, in which case do the safest thing. Drive safely and avoid accidents. Try not to succumb to road rage. If you’re going to speed, do it in a safe way - not in residential areas near playgrounds or schools. Speed limits aren’t there to slow you down for no reason, they’re there because most drivers don’t pay attention and pedestrians die at high speeds.

Pedestrians: be visible. Be predictable. Cross when you have the explicit right of way or when you’re sure you’re not impeding the flow of traffic. Look both ways before crossing, yes, even in crosswalks and even on one way streets. Make sure that cars have ample time (5+ seconds) to see you and stop before crossing. Reaction time is like 1-2 seconds, plus stopping time 2 seconds or so. It won’t kill you to wait 5 seconds, it might kill you if you don’t.