I could fill you a long list of dos and don'ts, what do look for and what to avoid, but cycling is inherently practical, and you have to learn it by doing it.
As you are by now aware, we're pretty much exposed to all kinds of dangers, and sometimes bad things happen. But if you aren't discouraged, and you keep on practicing, eventually you'll learn how to avoid most of the worst case scenarios where you could find yourself by your own negligence and/or lack of attention.
The important thing to retain is that you have to have the muscle memory to know how to react properly when in a tight spot. That's why reading about things isn't much of a help — you don't have time to think in order to act properly. My advice? Practice, and practice riding defensively.
I live in a very rough country for cyclists — Brazil. And in order to find my place on the road I have to be twice, thrice as careful as I would have to be somewhere else. But I've found that if you play it safe and learn to be nice and respectful of what the other perceives as its rightful place on the road, thanking everyone that shows you even the smallest act of kindness or basic respect for you, you'll be surprised how much things change on the road around you.
Be nice and don't try to be a hero. You're a glorified pedestrian and your skin is no match for steel.