As others have said, get a copy of Cyclecraft and start driving more defnsively. Just because others around you are "supposed" to signal, "supposed" to use their mirrors, you have found for yourself that they do not. Identify potential hazards and develop according strategies, eg not passing on the left when there is a left turn ahead, not stopping too close to vehicles that have stopped infront of you - the white van driver's attention was probably on the black car that appeared to be reversing into a parking spot - yes he should have been paying attention to his mirrors too, but you could have left more space which would havve given you more time to react and avoid being hit.
The key to this is to not expect others to do the "right" thing. Expect the worst possible case and act accordingly.