From experience, having been put in hospital, cycling 20 years in cities, and having lost count of my crashes, I have come to know exactly when I will crash, and that is when I don't follow the most important rule:
Complete and utter 100% absolute FOCUS, CONCENTRATION and AWARENESS
Even when some twat doesn't use their mirror, doesn't indicate, opens their door, cuts a cycle lane, whatever, I consider it my mistake if I crash because I didn't predict them. Every time I've ever crashed I've looked back and thought I could have predicted that, or the way I was cycling wasn't allowing for that to happen.
The only assumption I make is that people are not intentionally trying to kill me, without that assumption you can't even cross the road.
In order to have 100% focus:
a) Don't think about anything except how to make the next maneuver safely.
b) Have an objective, a place in your mind where you want to stop - NEVER EVER cycle in a city without a specific point in space you intend on arriving at.
c) If you find yourself lost, not knowing which way to turn, carry on with the flow, move with the traffic. Slow down, remain focused on moving with the traffic. Then only when you are nice and slow, pick a point to dismount. Then, once stationary, you can think about which way to go.
d) Ride as fast as you can while being aware of your stopping distance. Never ride casually, never enjoy the landmarks, get to your objective ASAP.