First rule: you are invisible. Be proactive.
They do not see you. Do not assume that they see you. Even before the days of personal portable technology, they didn’t see you. They may pass you 3 or 4 or 10 times but still they do not see you. It used to be they’d be watching for a parking space or reading a map or applying makeup and eating or just eager to get to that appointment on time. Now they’re looking at the Garmin and texting and dialing and eating. Their eyes are rarely on the road, why would they notice you on a bike? Given that you are invisible, act accordingly.
That Corolla, which you’ve passed 4 times, and is about to take a right turn at that corner a few feet ahead of you? Doesn’t see you so don’t assume that he’s going give way and let you pass him on his right. If he’s got his blinker on (a miracle in itself in this town) to take a right turn, go around and pass him on his left. Sometimes, if he’s in a real hurry, even if he does see you, he’ll hook you – cut you off to take the right hand turn. Better to get in the lane behind him if there’s a chance he’ll be making a turn.
For the above example, I’m thinking Mass. Ave. bridge heading from Boston to Cambridge and the intersection of Mass. Ave. and Mem. Drive. – or any of the other right-hand turn-offs of Mass. Ave.
That Taurus - creeping along Mass. Ave., slowing and speeding up, with her blinker on, weaving left and then right? She may be drunk, but more probably, she’s looking for an address or landmark. If she were texting or talking on her phone, she wouldn't have bothered with the directional. Either stay directly behind her or, when it’s safe to do so, get directly in front of her, so she can't help but see you.