Many of them likely aren't immediately useful to most people but here goes.

1 I got older, got a few degrees, got paid a bunch and have been living in areas with extremely low street crime. I could probably pass out in front of my house with a Benji sticking out of my fly and it would still be there in the morning.

2 I quit drinking. That wasn't an issue when I was a kid but later on it provided 2 huge benefits: 2.a) My situational awareness is never impaired. 2.b) It eliminated the vast majority of situations where someone might find me an interesting target.

3 I spent an absurd amount of time practicing and studying martial arts. The fighting parts of that aren't that useful but many RBSD (Reality Based Self Defense) classes are actually practical. tl;dr It's now fairly easy to find actual statistics on many forms of violence, look up the most likely ones for you, find the proven counters and practice those. For example, I've done a ton of drills that are a variation of shoving an attacker, yelling "Get away from me you PERVERT" (because while people tend to ignore cries for help, everyone wants to know who the pervert is), and running away.

4 Closely related to 3 is the general realization that you don't need to make yourself immune to violence. It's hard to be a good fighter and it's hard to make yourself the least attractive target. It's pretty easy to avoid being the most attractive target. For example, men are often targeted by men who want to exert dominance. Looking tough is counter productive because the attacker gets more glory from taking down a tough guy than a wimp. Looking batshit crazy is pretty effective; if I feel like I'm being followed and there isn't a convenient escape I smack my head a few times and start arguing with "the voices".