Apart from bike reflectors/blinking lights, I like the idea of a vest/bag. It's bigger than reflectors, and shows there's an actual human there. Instead of a vest, I have a bright green backpack that I use for my stuff, and I put the rain-cover on (bright yellow and reflective) when the sun starts to go down.
I also +1 to everything regarding acting like a vehicle. Don't ride on the sidewalk - cars won't expect something so fast to be coming at them from a sidewalk.
Ride on the road, stop at all signals and go when it's your turn. In terms of turning left on a busy road, I think it depends. For example, if there's a light or a stop, I will stop at the light/stop in the middle of the road (to be sure that no car can cut me off from the left), put my hand out to show that I'm turning left, and be the first to go when it's my turn. The thing not to do in that situation is stay on the right close to the sidewalk, and then expect to be able to turn left - that's dangerous. And in situations where you don't have a stop or light, you're probably right (because a car might not be expecting you to be stopped in the middle of the road).
Also, although technically not your "responsibility", always look a bit over your left shoulder if you're continuing straight when there could technically be a right turn. Cars don't look. You might get cut off. They won't care. Feel free to break hard, slap their car with your hand, and curse them out for causing you danger and being idiots (because you have the right of way), but don't forget to look nonetheless. It's your life.