Cars don't see you. Repeat. They don't see you. Even when they do, they don't register you as being significant enough to change their behavior, so you have to ride defensively. Be bright, visible, and assert your position, but keep your safety as the #1 priority (because it is).

I've got flashers front and rear, have a high-viz bike and jersey...and an AirZound. I see people trying to RT on red into my lane when I'm approaching the intersection, and even when I make eye contact, they think that I'm moving 10MPH, not 20-25 when I'm really moving. (On one downhill section, I'm going 35). So, whenever I see a car approaching and likely to cross my path, I've got a thumb poised on the AZ to make sure that if they don't see me, they're going to definitely hear me.

When cresting a hill, I'll stand up to see over the top. I've gotten used to holding my left hand up in a "STOP" gesture when I see oncoming traffic, but I've just as often given them a rolling "move around" gesture when I see that the way is clear. That extra 2 feet of vertical view when I'm standing up on the pedals comes in handy.

When I'm at the front of a LT lane and have already made it to the middle of the intersection to turn left, I'll also give them a "come on" gesture to have them turn inside to the inner lane (I'm going for the outer, since it's onto a 4-lane divided street). I've never had any problems with people swinging wide, and a lot of them seem to appreciate keeping traffic moving through the light.